Inorganic Heavy Metals Research Articles

Enhancing photocatalytic degradation of crystal violet dye with g‐C3N4/ZnTiO3 nanocomposites synthesized via a facile approach

AbstractPhotocatalysts that exhibit exceptional performance could be further enhanced for wastewater treatment, particularly in the degradation of organic pollutants and reduction of inorganic heavy metal ions concentrations. This study employed sol–gel techniques was used to create a Type II scheme g‐C3N4/ZnTiO3 (CZT‐2, CZT‐4, and CZT‐6) photocatalyst. FT‐IR, UV‐DRS, XRD, SEM, BET, HR‐TEM, and XPS analysis were conducted to investigate the physical and chemical properties of the g‐C3N4/ZnTiO3 photocatalyst's. An investigation was conducted to evaluate the photocatalytic performance of the synthesized samples. The samples exhibit remarkable efficacy in the degradation of organic contaminants. Among them, CZT‐2 showcased superior photocatalytic performance in the solar light‐induced photodegradation of crystal violet. The photocatalytic activity of g‐C3N4/ZnTiO3 has been significantly enhanced through the establishment of a Type‐II scheme at the interface. This innovative approach efficiently facilitates the separation of photogenerated electron–hole pairs, thereby boosting the photodegradation activity. The discussion also included the chemical process between photocatalysts and crystal violet. The mechanism of the crystal violet‐photocatalyst reaction was also discussed. After undergoing five cycles of reuse, the photocatalyst that was manufactured demonstrated remarkable stability, leading to a reduction in the cost associated with wastewater treatment. The as‐synthesized g‐C3N4/ZnTiO3 composites are very safe for the environment, which suggests that the CZT‐2 composite is very good at getting rid of pollutants.

Reactive oxygen species-mediated organic long-persistent luminophores light up biomedicine: from two-component separated nano-systems to integrated uni-luminophores.

Organic luminophores have been widely utilized in cells and in vivo fluorescence imaging but face extreme challenges, including a low signal-to-noise ratio (SNR) and even false signals, due to non-negligible background signals derived from real-time excitation lasers. To overcome these challenges, in the last decade, functionalized organic long-persistent luminophores have gained much attention. Such luminophores could not only overcome the biological toxicity of inorganic long-persistent luminescent materials (metabolic toxicity and leakage risk of inorganic heavy metals), but also continue to emit long-persistent luminescence after removing the excitation source, thus effectively improving imaging quality. More importantly, organic long-persistent luminophores have good structure tailorability for the construction of activable probes, which is favorable for biosensing. Recently, the development of reactive oxygen species (ROS)-mediated long-persistent (ROSLP) luminophores (especially organic small-molecule ROSLP luminophores) is still in the rising stage. Notably, ROSLP luminophores for in vivo imaging have experienced from two-component separated nano-systems to integrated uni-luminophores, which obtained gradually better designability and biocompatibility. In this review, we summarize the progress and challenges of organic long-persistent luminophores, focusing on their development history, long-persistent luminescence working mechanisms, and biomedical applications. We hope that these insights will help scientists further develop functionalized organic long-persistent luminophores for the biomedical field.

Superoxide Anion-Mediated Afterglow Mechanism-Based Water-Soluble Zwitterion Dye Achieving Renal-Failure Mice Detection.

Afterglow materials-based biological imaging has promising application prospects, due to negligible background. However, currently available afterglow materials mainly include inorganic materials as well as some organic nanoparticles, which are difficult to translate to the clinic, resulting from non-negligible metabolic toxicity and even leakage risk of inorganic heavy metals. Although building small organic molecules could solve such obstacles, organic small molecules with afterglow ability are extremely scarce, especially with a sufficient renal metabolic capacity. To address these issues, herein, we designed water-soluble zwitterion Cy5-NF with renal metabolic capacity and afterglow luminescence, which relied on an intramolecular cascade reaction between superoxide anion (O2•-, instead of 1O2) and Cy5-NF to release afterglow luminescence. Of note, compared with different reference contrast agents, zwitterion Cy5-NF not only had excellent afterglow properties but also had a rapid renal metabolism rate (half-life period, t1/2, around 10 min) and good biocompatibility. Unlike prior afterglow nanosystems possessing a large size, for the first time, zwitterion Cy5-NF has achieved the construction of water-soluble renal metabolic afterglow contrast agents, which showed higher sensitivity and signal-to-background ratio in afterglow imaging than fluorescence imaging for the kidney. Moreover, zwitterion Cy5-NF had a longer kidney retention time in renal-failure mice (t1/2 more than 15 min). More importantly, zwitterion Cy5-NF can be metabolized very quickly even in severe renal-failure mice (t1/2 around 25-30 min), which greatly improved biosecurity. Therefore, we are optimistic that the O2•--mediated afterglow mechanism-based water-soluble zwitterion Cy5-NF is very promising for clinical application, especially rapid detection of kidney failure.

Strategic use of crop residue biochars for removal of hazardous compounds in wastewater

Crop residues are affordable lignocellulosic waste in the world, and a large portion of the waste has been burned, releasing toxic pollutants into the environment. Since the crop residue is a carbon and ingredient rich material, it can be strategically used as a sorptive material for (in)organic pollutants in the wastewater after thermo-chemical valorization (i.e., biochar production). In this review, applications of crop residue biochars to adsorption of non-degradable synthetic dyes, antibiotics, herbicides, and inorganic heavy metals in wastewater were discussed. Properties (porosity, functional groups, heteroatom, and metal(oxide)s, etc.) and adsorption capacity relationships were comprehensively reviewed. The current challenges of crop residue biochars and guidelines for development of efficient adsorbents were also provided. In the last part, the future research directions for practical applications of the crop residue biochars in wastewater treatment plants have been suggested.

Research on the reaction mechanism of 2,4,6‐trinitrotoluene resource utilization I: Formation of 2,4,6‐trinitrobenzoic acid in acetic acid with N,N′,N″‐trihydroxyisocyanuric acid catalyst

AbstractAs an organic molecule catalyst, N,N′,N″‐trihydroxyisocyanuric acid can selectively catalyze the oxidation of the methyl group of waste 2,4,6‐trinitrotoluene to generate 2,4,6‐trinitrobenzoic acid. This reaction can avoid environmental pollution by inorganic heavy metal catalysts. In this study, four reaction stages of this catalytic reaction were designed and validated computationally at the M06‐2X‐D3ZERO/6‐311G(d,p) level using the acetic acid solvent model. These validations include transition state searches, intrinsic reaction coordinate calculations, reactant and product optimizations, and frequency calculations. The final reaction network of 23 transition states shows that after N,N′,N″‐trihydroxyisocyanuric acid activation and common reaction, the network bifurcates into two stages: alcohol to carboxylic acid and aldehyde to carboxylic acid. Although the former stage releases about 155 kcal/mol of Gibbs free energy, less than the 177 kcal/mol from the latter stage, the overall reaction equation shows that the pathway including former stage does not consume the catalytically active substance IM_T2, which saves the energy required for reactivation and is thus more favorable. Furthermore, the key transition states in the reaction network include bimolecular substitution reactions and proton‐hopping transfer reactions. Analyses of their interaction region indicators and intrinsic reaction coordinate results demonstrate strong selectivity. Additionally, the energy barriers and heat releases of the latter are twice and 1.3 times greater than those of the former, respectively. In summary, this study elucidated two competitive reaction pathways and identified the more energetically favorable and selective pathway, and it provides useful insights for further optimization of industrial utilization of 2,4,6‐trinitrotoluene.

Phytotechnology with Biomass Production Sustainable Management of Contaminated Sites. By Larry E.Erickson, ValentinaPidlisnyuk (Eds.), Boca Raton, FL: CRC Press, Taylor & Francis Group. 2021. pp. 242. U.S. List Price: $140.00. ISBN: 978‐0‐367‐52280‐3 (hardback); ISBN: 978‐1‐003‐08261‐3 (ebook); ISBN: 978‐0‐367‐53620‐6 (paperback)

The vast amount of global industrialization has created enormous amounts of environmental pollutants. The accumulation of these metals in the soil, groundwater and waste streams has caused polluted lands to be unsuitable for human inhabitation and agriculture. Furthermore, these inorganic heavy metals are of primary concern because they cannot be destroyed by degradation. Consequently, many plants species have been successful in absorbing contaminants (i.e., inorganic and organic metals) and various radionuclides from soils. The remediation process to address contaminated soil problems that uses vascular plants, fungi and algae to either assist with the breakdown of waste using microorganisms or remove and control wastes is known as phytotechnology. Phytotechnology has received scientific and public acceptance due to it being environmentally friendly and a cost-effective approach for cleaning up the environment. Phytotechnology with Biomass Production: Sustainable Management of Contaminated Sites provides unique insight of the Miscanthus production on postmining and postmilitary contaminated sites and the impact of plant growth regulators and soil amendments- biochar, fertilizers, compost, and so forth. This book uses the Miscanthus (silvergrass) plant to implement remediation processes and explain concepts of phytotechnology with biomass production to improve soil quality and return contaminated property to productive use that has social and economic value. Based on case study research from the United States, the Czech Republic, Germany, Ukraine and other countries, this book primarily focuses on the application of the bio-fuel crop, Miscanthus, to contaminated soil. Other important concepts discussed included: plant microbe-based technology, phytomanagement, phytomining, phytostabilization, and bioenergy. Introduction Larry E. Erickson (Kansas State University) and Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic) Phytotechnologies for Site Remediation Valentina Pidlisnyuk (Kansas State University), Ganga M. Hettiarachchi (Kansas State University), Zeljka Zgorelec (University of Zagrev, Croatia), Melissa Prelac (Paying Agency for Agriculture, Fisheries, and Rural Development, Croatia), Nikola Bilandzija (University of Zagrev, Croatia), Lawrence C. Davis (Kansas State University), and Larry E. Erickson (Kansas State University) Remediation of Sites Contaminated by Organic Compounds Lawrence C. Davis (Kansas State University), Barbara Zeeb (Royal Military College of Canada, Kingston), Larry E. Erickson (Kansas State University), Aigerim Mamirova (Al-Farabi Kazakh National University, Kazakhstan) and Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic) Phytomining Applied for Postmining Sites Hermann Heilmeier (Technische Universitat Bergakademie Freiberg, Germany) Establishing Miscanthus, Production of Biomass, and Application to Contaminated Sites Lawrence C. Davis (Kansas State University), Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic), Aigerim Mamirova (Al-Farabi Kazakh National University, Kazakhstan), Pavlo Shapoval (National University Lvivska Polytechnika, Ukraine), and Tatyana Stefanovska (National University of Life and Environmental Science of Ukraine) Balancing Soil Health and Biomass Production Larry E. Erickson (Kansas State University) and Kraig Roozeboom (Kansas State University) Plant-Microbe Associations in Phytoremediation Asil Nurzhanova (Institute of Plant Biology and Biotechnology, Kazakhstan), Aigerim Mamirova (Al-Farabi Kazakh National University, Kazakhstan), Josef Trogl (Jan Evangelista Purkyne University, Czech Republic), Diana Nebeska (Jan Evangelista Purkyne University, Czech Republic), and Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic) Economics of Phytoremediation with Biomass Production Larry E. Erickson (Kansas State University), Jan Cerny (Jan Evangelista Purkyne University, Czech Republic), and Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic) Miscanthus Biomass for Alternative Energy Production Jikai Zhao (Kansas State University) Donghai Wang (Kansas State University), Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic), and Larry E. Erickson (Kansas State University) Miscanthus as Raw Materials for Bio-based Products Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic), Larry E. Erickson (Kansas State University), Donghai Wang (Kansas State University), Jikai Zhao (Kansas State University), Tatyana Stefanovska (National University of Life and Environmental Science of Ukraine), and John R. Schlup (Kansas State University) Conclusions and Recommendations Larry E. Erickson (Kansas State University), Valentina Pidlisnyuk (Jan Evangelista Purkyne University, Czech Republic), and Lawrence C. Davis (Kansas State University) As a Civil/Environmental Engineering PhD from the University of Alabama at Birmingham (UAB) and had been engaged in phytoextraction of Cr6+, I find this book to be an excellent resource. This book provides critical and valuable information and does a great job of explaining the basics while providing numerous examples of successful application of Miscanthus to contaminated soil and various treatment technologies. One excellent feature of this book is the introduction/overview of new techniques and tools for monitoring and removing environmental contaminants, for example, phytomanagement, phytoextraction, and phytostabilization. I believe this handbook does a tremendous job of compiling useful information for research and industry about innovative phytotechnology research which is cited throughout this book. In my opinion, researchers, students, and professionals from a wide variety of disciplines would find this book as a very useful addition to their libraries. Reviewed by: Sandra Cutts, PhD., ORISE Post-Doctoral Researcher, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue, N.W., Washington, D.C. Email: [email protected] Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

Methylmercury, Mn2+ and Pb2+ Exposure Promotes Premature Proliferation/Differentiation of Human Neural Stem Cells in Different Ways

Abstract: Background: Methylmercury (MeHg), manganese ions (Mn2+), and lead ions (Pb2+) are ubiquitous environmental pollutants and may be neurotoxic especially during fetal development. We decided to explore the toxic mechanisms of MeHg (organic heavy metals), Mn2+ (inorganic heavy metals) and Mn2+ on the proliferation and differentiation of human neural stem cells (hNSCs). Materials and Methods: The proliferation and apoptosis of hNSCs were analyzed via CCK-8 method and flow cytometry under MeHg, Mn2+ and Pb2+, respectively. RNA-seq was used for analyzing proliferation/differentiation mechanism of MeHg, Mn2+ and Pb2+ stressing hNSCs. Results: Our experiment found that when hNSCs were exposed to below 0.5 nM MeHg, 5μM Mn2+ and 10 μM Pb2+, cell proliferation and differentiation were promoted. Apoptosis rates increased significantly when hNSCS were exposed to exceed 0.5 nM MeHg, 5μM Mn2+ and 10 μM Pb2+. RNA-seq results showed that metal ions altered the genes expression level and signaling pathways of hNSC differentiation and proliferation, but the regulatory mechanisms of MeHg, Mn2+ and Pb2+ were different. Conclusion: Our findings indicated that very low-dose metal exposure may deplete hNSC pool by making prematurely differentiated neurons increase, which may be the real cause of long-term nervous system disruption in adulthood, rather than higher metal doses will cause more direct toxicity during infant development. Keywords: Methylmercury, Manganese ion, Lead ion, Neural stem cells, Cell differentiation

Porous organic polymers (POPs) for environmental remediation.

Modern global industrialization along with the ever-increasing growth of the population has resulted in continuous enhancement in the discharge and accumulation of various toxic and hazardous chemicals in the environment. These harmful pollutants, including toxic gases, inorganic heavy metal ions, anthropogenic waste, persistent organic pollutants, toxic dyes, pharmaceuticals, volatile organic compounds, etc., are destroying the ecological balance of the environment. Therefore, systematic monitoring and effective remediation of these toxic pollutants either by adsorptive removal or by catalytic degradation are of great significance. From this viewpoint, porous organic polymers (POPs), being two- or three-dimensional polymeric materials, constructed from small organic molecules connected with rigid covalent bonds have come forth as a promising platform toward various leading applications, especially for efficient environmental remediation. Their unique chemical and structural features including high stability, tunable pore functionalization, and large surface area have boosted the transformation of POPs into various macro-physical forms such as thick and thin-film membranes, which led to a new direction in advanced level pollutant removal, separation and catalytic degradation. In this review, our focus is to highlight the recent progress and achievements in the strategic design, synthesis, architectural-engineering and applications of POPs and their composite materials toward environmental remediation. Several strategies to improve the adsorption efficiency and catalytic degradation performance along with the in-depth interaction mechanism of POP-based materials have been systematically summarized. In addition, evolution of POPs from regular powder form application to rapid and more efficient size and chemo-selective, "real-time" applicable membrane-based application has been further highlighted. Finally, we put forward our perspective on the challenges and opportunities of these materials toward real-world implementation and future prospects in next generation remediation technology.

Simultaneous removal of organic micropollutants and inorganic heavy metals by nano-calcium peroxide induced Fenton-like treatment

Groundwater can be contaminated by both organic micropollutants and inorganic heavy metals and thus, it is essential to develop environmental-friendly and cost-effective technologies for the remediation of such multiple contaminants. Advanced nanomaterials, including nano-calcium peroxide (nano-CaO2), induced Fenton-like treatment has been recently developed to effectively oxidise and remediate various organic micropollutants. The Ca(OH)2 residues have the potential to further remove toxic heavy metals via precipitation, however, it has been rarely studied. To investigate the proposed feasibility and understand the mechanisms, an optimised pH-regulated chemical precipitation method was developed to synthesis the nano-CaO2 material and then catalysed by Fe(II) towards simultaneous removal of the model compounds of p-nitrophenol (PNP) and cadmium (Cd). The Electron Spin Resonance (ESR) measurements demonstrated that hydroxyl radicals (∙OH) and singlet oxygen (1O2) are two major reactive oxygen species that lead to 93 % removal of PNP under the initial concentration of 40 mg/L. Simultaneously, over 99 % of the Cd (initial concentration of 10 mg/L) was removed through the precipitation with Ca(OH)2 and/or co-precipitation with ferrite. Such best removal performances were achieved under the optimal dose ratio of nano-CaO2 and Fe(II) at 500 mg/L to 75 mg/L, respectively. The existence of sunlight illumination and competition ions, i.e. K+, Na+, Ca2+, Mg2+, SO42-, NO3–, and Cl−, showed negligible effect on the removal performance, which supported its feasibility for the treatment of both ground- and surface water. Increasing the pH to 9, the time to remove 99 % Cd would be shortened from 60 min to 30 min, however, the degradation of PNP would dramatically reduce from 93 % to 20 % with 180 min. The removal performance was not affected by a large range of anions and cations, such as Na+, K+, Ca2+, Mg2+, Fe3+, SO42−, Cl− and NO3– ions, however, the existence of HCO3– and Mn2+ should be taken into consideration during the application as they could lead to obvious impacts on the treatment. Overall, this study provided a new insight of removing organic micropollutants and inorganic heavy metals simultaneously from groundwater via mechanisms revealed ex-situ nano-remediation technique.

Review of Clay-Based Nanocomposites as Adsorbents for the Removal of Heavy Metals

Due to rapid industrialization, urbanization, and surge in modern human activities, water contamination is a major threat to humanity globally. Contaminants ranging from organic compounds, dyes, to inorganic heavy metals have been of major concern in recent years. This necessitates the development of affordable water remediation technologies to improve water quality. There is a growing interest in nanotechnology recently because of its application in eco-friendly, cost-effective, and durable material production. This study presents a review of recent nanocomposite technologies based on clay, applied in the removal of heavy metals from wastewater, and highlights the shortcomings of existing methods. Recently published reports, articles, and papers on clay-based nanocomposites for the removal of heavy metals have been reviewed. Currently, the most common methods utilized in the removal of heavy metals are reverse osmosis, electrodialysis, ion exchange, and activated carbon. These methods, however, suffer major shortcomings such as inefficiency when trace amounts of contaminant are involved, uneconomical costs of operation and maintenance, and production of contaminated sludge. The abundance of clay on the Earth’s surface and the ease of modification to improve adsorption capabilities have made it a viable candidate for the synthesis of nanocomposites. Organoclay nanocomposites such as polyacrylamide-bentonite, polyaniline-montmorillonite, and β-cyclodextrin-bentonite have been synthesized for the selective removal of various heavy metals such as Cu2+, Co2+, among others. Bacterial clay nanocomposites such as E. coli kaolinite nanocomposites have also been successfully synthesized and applied in the removal of heavy metals. Low-cost nanocomposites of clay using biopolymers like chitosan and cellulose are especially in demand due to the cumulative abundance of these materials in the environment. A comparative analysis of different synthetic processes to efficiently remove heavy metal contaminants with clay-based nanocomposite adsorbents is made.

Prospects for the Use of Echinochloa frumentacea for Phytoremediation of Soils with Multielement Anomalies

In a model experiment, some adaptive characteristics, the bioaccumulation of toxic elements from technogenically-contaminated soils with polyelement anomalies, and rhizosphere microflora of Japanese millet, Echinochloa frumentacea, were studied using biochemical, microbiological, physicochemical (AAS, ICP-MS, INAA), and metagenomic (16S rRNA) methods of analysis. Good adaptive characteristics (the content of photosynthetic pigments, low molecular weight antioxidants) of E. frumentacea grown on the soils of metallurgical enterprises were revealed. The toxic effect of soils with strong polyelement anomalies (multiple excesses of MPC for Cr, Ni, Zn, As, petroleum products) on biometric parameters and adaptive characteristics of Japanese millet were shown. The rhizosphere populations of E. frumentacea grown in the background soil were characterized by the lowest taxonomic diversity compared to the rhizobiomes of plants grown in contaminated urban soils. The minimal number of all groups of microorganisms studied was noted in the soils, which contain the highest concentrations of both inorganic (heavy metals) and organic (oil products) pollutants. The taxonomic structure of the rhizospheric microbiomes of E. frumentacea was characterized. It has been established that E. frumentacea accumulated Mn, Co, As, and Cd from soils with polyelement pollution within the average values. V was accumulated mainly in the root system (transfer factor from roots to shoots 0.01–0.05) and its absorption mechanism is rhizofiltration. The removal of Zn by shoots of E. frumentacea increased on soils where the content of the element exceeded the MPC and was 100–454 mg/kg of dry weight (168–508 g/ha). Analysis of the obtained data makes it possible to recommend E. frumentacea for phytoremediation of soil from Cu and Zn at a low level of soil polyelement contamination using grass mixtures.

Geo Spatial Based Real Time Monitoring on Eutrophic Evaluation of Porunai River Basin for Pollution Risk Assessment

ABSTRACT The basic amenity for a highly civilized community needs water and drainage facilities; with uncontrolled population outrage, there arises demand for water consumption which naturally leads to effluent discharge. Even though the district has ample landscape, smart drainage facilities, the rainwater and storm runoff are still collected as pumped source for treatment to a long distance. These wastewaters diverted to the river surface due to insufficient retention time for treatment that naturally grounds a serious ecological damage. The concentration of organic and inorganic heavy metals determines the nature of contamination whether lighter low concentrated or severe high concentrated, meanwhile the level get diluted with streaming in the river surface. Deposited contaminants along the Porunai river basin are in dissolved stages that naturally lead to eutrophication which will cause pollution risk and indirectly affects the dependents covering three districts. With the support of GIS, online monitoring is incorporated to check the gathering of phosphorus, removal of phosphorus from the soil and nitrogen removal. The aim of the research focus is to study eutrophic nutrient limits in river Porunai which is a streaming of Thamirabarani and manimuthar. Nutrient removals from the designed reactors express the available measure of pollution risk. Life cycle study gives the life term of river front and a blueprint is framed based on reducing the mixing of unwanted water sources. In due course make it a place of recreation prevailing with current scenario and future prediction by means of statistical data compared with navigation studies.

A critical review of advanced nanotechnology and hybrid membrane based water recycling, reuse, and wastewater treatment processes

One of the modern challenges is to provide clean and affordable drinking water. Water scarcity is caused by the growing population in the world and pollutants contaminate all remaining water sources. Innovative water treatment solutions have been provided by nanotechnology. Microorganisms, organic suspensions, and inorganic heavy metal ions, among other things, are common water contaminants. Since antiquity, a wide range of water clean-up methods have been employed to address this issue. Breakthroughs in water purification procedures have occurred during the previous four decades, with the most significant one being the use of nanomaterials and nanomembranes. Nanoparticles and nanomembranes (polymeric membranes) have recently been used in engineered materials (TiO2, ZnO, CuO, Ag, CNT's and mixed oxide nanoparticles, for example). Engineered nanomembranes, nanocomposites and nanoparticles have been used in this review article's discussion of water purification technologies. The review also discusses the risk and solutions of using nanoparticles and nanocomposites in the future.

Efficient removal of water pollutants by hierarchical porous zeolite-activated carbon prepared from coal gangue and bamboo

The inorganic heavy metal ions (IHMIs) and organic macromolecular pollutants (OMPs) are the two most common pollutants in industrial, agricultural and municipal wastewater. They have greatly threatened the environmental security and human health because of their most notorious toxicity and carcinogenicity. In this study, a composite of zeolite-activated carbon is synthesized taking coal gangue as silicon and aluminum sources and adding bamboo as carbon source through a facile calcining process following a hydrothermal process. The obtained zeolite-activated carbon composite is a kind of hierarchical porous structure, which contains a large number of micro-pores, meso-pores and macro-pores simultaneously. The zeolite-activated carbon with high specific surface area of 879.1 m2/g is used to absorb IHMIs and OMPs. It shows high adsorption capacities for copper ions (Cu2+, 104.9 mg/g) and Rhodamine-B (Rh–B, 83.34 mg/g). The zeolite with a large number of micro-pores could chain a lot of IHMIs with small diameters, and the activated carbon could allow large size OMPs into its meso-pores and macro-pores. The thermodynamic and kinetic studies indicate that the adsorption of adsorbates onto the zeolite-activated carbon composite is assigned to a monolayer, spontaneous and physical adsorption. Thus the zeolite-activated carbon composite could adsorb the pollutants quickly and desorb them repeatedly. This research not only effectively deals with the IHMIs and OMPs in the waterbody, but also converts the coal gangue into high value-added product. Therefore, this study provides a facile method to synthesize zeolite-activated carbon composite from solid waste and biomass material. The prepared zeolite-activated carbon composite could be selected as a potential candidate for sewage treatment.

Effect of Cu2+ and Cd2+ on the growth and sulfidogenic activity of sulfate-reducing bacteria under using aromatic hydrocarbons

Purification of the aquatic environment from substances of organic and inorganic matter is an urgent problem nowadays. Falling into the water of insufficiently treated effluents significantly impairs water quality and the condition of water bodies in general. Aromatic compounds, in particular toluene and xylene, are quite common pollutants in the aquatic environment. In addition to compounds of organic nature, wastewater contains many inorganic substances and heavy metal ions. Among the common methods of detoxification of the environment, biological ones play a leading role, as they are cost-effective and environmentally safe. One of the promising methods of purification is the usage of microorganisms, in particular sulfate-reducing bacteria. The influence of heavy metal ions on the accumulation of biomass and hydrogen sulfide by Desulfotomaculum sp. AR1 and D. desulfuricans Ya-11 bacteria during the growth in a medium with toluene and xylene is studied. The ability of sulfate-reducing bacteria Desulfotomaculum sp. AR1 and D. desulfuricans Ya-11 to grow with the simultaneous presence of aromatic compounds and heavy metal ions into the environment indicates their high potential in the usage to purify the aquatic environment from these contaminants. The inhibitory effect of metal ions on the process of reduction of sulfate ions by the studied bacteria, and, as a consequence, the accumulation of less toxic hydrogen sulfide, is shown. The influence of the source of carbon (sodium lactate/xylene/toluene) and heavy metal ions on the growth of bacteria Desulfotomaculum sp. AR1 and D. desulfuricans Ya-11 is analysed. It is shown that the accumulation of biomass by bacteria Desulfotomaculum sp. AR1 and D. desulfuricans Ya-11 are affected by both the nature of the electron donor and the presence of Cu2+ and/or Cd2+ ions in the medium. Penetrating into living cells, heavy metal ions disrupt their vital functions, but heavy metals are toxic only in the form of ions, but if they are translated into a bound form, they lose their toxic properties. The ability of the studied bacteria to precipitate Cu2+ and Cd2+ ions in the form of insoluble metal sulfides was revealed. Thus, the content of hydrogen sulfide in the aqueous medium can be adjusted, and in turn, it can be purified from heavy metal ions. According to the obtained results, sulfate-reducing bacteria Desulfotomaculum sp. AR1 and D. desulfuricans Ya-11 can be considered as promising in the development of methods for purification of the aquatic environment from heavy metal ions, in particular Cu2+ and Cd2+

Adsorption-photocatalysis synergistic removal of contaminants under antibiotic and Cr(VI) coexistence environment using non-metal g-C3N4 based nanomaterial obtained by supramolecular self-assembly method

Due to the rapid development of modern industry, the coexistence of antibiotics and inorganic heavy metals pollutants in wastewater has become a universal phenomenon. Therefore, developing efficient and eco-friendly photocatalyst for mixed pollutants degradation is significant. In this work, a well-designed phosphorus and sulfur co-doped g-C3N4 with feeble N vacancies catalyst (P/S-g-C3Nx) was fabricated by supramolecular self-assembly method, and was applied to remove berberine hydrochloride (BH) and Cr(VI) simultaneously with the synergy of adsorption-photocatalysis. A series of experiments was conducted to unveil the synergistic mechanism. The kinetic models indicated that the adsorption of P/S-g-C3Nx improved the BH removal process by accelerating the photo-degradation, because the adsorption rate > surface degradation rate > bulk degradation rate. Besides, the photo-degradation process improved the BH removal rate by regenerating the adsorption sites of P/S-g-C3Nx. Moreover, from the experiments in BH-Cr(VI) mixed solution system, the existence of BH also enhanced the surface adsorption of Cr(VI) in P/S-g-C3Nx sample, and the reduction rate of Cr(VI) was also promoted with the existence of BH. Overall, the results of this investigation suggest that the adsorption-photocatalysis synergy method is an efficient way to eliminate organic pollutant and Cr(VI) simultaneously.

An innovative strategy for synchronous treatment of combined heavy metal and organic pollutants through polysaccharide gel encapsulating S2−

In many industrial fields, treatment of composite contaminations involving inorganic heavy metal ions and organic pollutants simultaneously remains a tremendous challenge. In this paper, an innovative strategy based on the gelation process of Sodium Alginate (SA) was proposed for synchronous treatment of composite pollutants. Through a pre-gelation step, SA gel balls encapsulated with S2− (SA/S2− gel) were formed and immersed into polluted solutions containing Pb2+/Cd2+ and Cd2+/dye. The removal efficiency of Pb2+/Cd2+ by SA/S2− gel were both increased compared with pure SA gel. The adsorbed Pb2+/Cd2+ was in-situ transformed into PbS/CdS quantum dots (QDs) possessing photo-catalytic activity, which induced the degradation of dyes under UV irradiation. In this respect, the proposed SA/S2− system might provide a high-performance and energy-saving way for comprehensive treatment of inorganic heavy metal and organic industrial pollutants.

Novel smart composite materials for industrial wastewater treatment and reuse

With the current levels of industrial development it is very difficult to prevent organic pollutants and toxic heavy metals from contaminating water. Thus purification of contaminated industrial water and its reuse is a global concern. The present study highlights application of a novel standalone technology in the form of polymers that efficiently extract a range of organic and inorganic impurities simultaneously for reuse of industrial effluent. Previous studies have focused on water soluble synthetic polymers for removal of organic contaminants, while biodegradable polymers are being used for extraction of toxic metals from water. Our earlier reports already describe a combination of synthetic and natural polymers with the ability to eliminate organic and inorganic spiked impurities from water on a lab scale. In the present work a series of novel smart composite materials have been synthesized and fully characterized. The avant-garde novelty of these materials for simultaneous removal of organic impurities such as phenols, anhydrides, textile dyes, pesticides, herbicides, antibiotics and inorganic heavy metals has been demonstrated and the novel polymers have shown a removal efficiency of more than 90% for each of the contaminants. Furthermore, the established 4-cycle reusability and an extensive reduction in levels of chemical oxygen demand suggests these materials would act as an improvement to the current methods for treating effluent water. The high reproducibility in synthesis, properties and elimination spectrum brands them as promising materials for industrial water remediation and reuse.

Review on the effects of heavy metal pollution on herbivorous insects

Heavy metal pollution is one of the thorniest issues in the world, which is a serious threat to ecosystems and food security. As an important link of food chain and food web in the ecosystem, herbivorous insects play important role in the transfer and accumulation of heavy metals. Consequently, more and more attentions have been paid on the potential effects of heavy metal pollution on herbivorous insects. Here, we reviewed the effects of heavy metal pollution on herbivorous insects with literature publshied during 2007 to 2018. Herbivorous insects were exposed to heavy metals pollution via four ways, including insect diets or food added with inorganic heavy metals, field exposure with heavy metals, "soil/substrate-plants-herbivorous insect" food chain and in vitro injection. Excessive accumulation of heavy metals in insect body results in decreased survival rate, reproductive capacity and population growth, the retarded growth and development. Physiological and biochemical toxicity of heavy metal pollution to herbivorous insects included cell ultra-structure destruction and DNA damage, decreased amount of energy materials, and changes in enzymes acti-vity and gene expression levels. However, herbivorous insects can resist heavy metal stress by producing metallothionein and enhancing activity of detoxification enzymes etc., which probably results in their adaptive evolution to heavy metal stress at low intensity or long-term and even improve their tolerance to other stresses (e.g., pesticides).

Activated biochar derived from Opuntia ficus-indica for the efficient adsorption of malachite green dye, Cu+2 and Ni+2 from water

Applicability of biochar in water treatment is gaining interest due to its sustainability and low production cost. Herein, the biochar (BC) and activated biochar (ABC) synthesized from the cladodes of Opuntia ficus-indica (OFI) cactus were evaluated as a renewable adsorbent for adsorption of organic as well as inorganic pollutants including malachite green (MG) dye, Cu+2 and Ni+2 heavy metals. The modification of biochar with NaOH resulted higher surface basicity regarding more oxygen containing functional groups on the surface. The maximum uptake of 1341 mg g−1, 49 mg g−1 and 44 mg g−1 onto activated biochar for malachite green dye, Cu+2 and Ni+2 was acquired through the best fitted Langmuir isotherm model. Pseudo-second-order and Elovich models were found to provide a suitable fit indicating towards the chemisorption of all three components. Film diffusion and chemisorption are the main steps in adsorption of MG dye and heavy metals on activated biochar. The adsorption mechanisms were also hypothesized for adsorption of MG dye, Cu+2 and Ni+2. The remarkable adsorption capacities with higher reusability characteristics for adsorption of organic pollutants as well as inorganic heavy metals entrusts this activated biochar as a potential cost-effective adsorbent to mitigate water pollution issue.