Removal Of Contaminants In Water Research Articles

Efficient and easily recyclable photocatalytic reduction of Se(IV) from wastewater using stable TiO2/BiOBr/cloth: Mechanism insight and machine learning modeling

Photocatalytic technology is extensively employed for the reductive removal of water contaminants; however, it contends with low catalytic efficiency and challenges in catalyst recovery. In this study, we propose integrating experimental procedures with artificial intelligence modeling to enhance the purification of Se(IV)-contaminated wastewater. We present an efficient, easily recyclable, and cost-effective strategy for photocatalyst fabrication. Specifically, we develop a novel method for Se(IV) removal by immobilizing TiO2/BiOBr onto glass fiber cloth surfaces using chitosan for Se(IV) reduction in aqueous solutions. The TiO2/BiOBr/cloth (TB-4/cloth) catalyst achieves a remarkable 99.2 % Se(IV) removal within 2 h under visible light and maintains excellent Se(IV) reduction photocatalytic activity (86.4 %) even after eight cycles, remaining easily reusable. Additionally, we develop two machine learning models, namely artificial neural network (ANN) and long short-term memory (LSTM), to validate the anticipated experimental outcomes. Both models exhibit high accuracy and predictive capability (R2 > 0.99, RMSE < 0.03). This study introduces a novel approach that combines experimentation with artificial intelligence modeling, paving the way for future advancements in Se(IV)-contaminated wastewater purification methods.

Removal of Contaminants in Water with Scallop Shell Waste

Currently, the cultivation and harvesting of mollusks is a crucial activity worldwide. However, this industry generates a large amount of mollusk shell waste disposed of in landfills, causing environmental pollution. In addition, the companies linked to this item allocate large sums of money to depositing the shells in authorized landfills. In South America, Chile is one of the leading producers worldwide of scallop shell (Argopecten purpuratus) waste, creating a growing environmental and financial problem in the country, especially considering that there has yet to be progress in the development of new technologies that may reuse this waste in Chile. This study used different techniques to completely characterize the northern Chile scallop shell waste’s physical and chemical properties for the first time. The XRD result corresponded with calcite crystal structures (CaCO3), and the XFR showed 97.68% purity. Three particle sizes were obtained: BS (595–100 µm), MS (250–595 µm), and SS (&lt;250 µm). In addition, the potential use of these wastes to remove contaminants present in water from the wine industry (caffeic acid) and some drinking water (arsenic(III)) was evaluated. The powder with the smallest particle size (SS), which has a surface area of 1 m2/g, 0.0050 m3/g of pore volume and pore diameter of 18.0 nm, removed 100.0% of CA and 23.0% As(III) in a pH condition of 4.6. The results show that scallop shell waste can be used to treat water and reinforce polymeric matrix composite materials to improve mechanical properties.

Carbon Nanotubes as Adsorbents for Heavy Metals: Focus on Arsenic and Hydrargyrum Removal from Water

Water is the most common and indissoluble substance in the ecosystem. It is really sad that the development of cities, people, and industries has side effects on water resources, as they are getting worse. Heavy metals are mostly found in industries; their toxicity levels are a big challenge. The work details the latest methods employed in the removal of water contaminants with heavy metals, absorption being the technique used. Following the completeness of the literature review for various sorbents that are used to remove heavy metals from wastewater, this article details one of the possible sorbents that can play this role, using carbon nanotubes as a sorbent. Through the test, it has been demonstrated that CNTs have high efficiency, yet some shortcomings have also been shown. It should, additionally, be known that further improvement of desulfurizing agents to make them better at removing heavy metals is needed. This work demonstrates that, in comparison to IL's, which must be supplied by producers, DES's, as an alternative approach, are cheaper, more accessible to use, and much safer for the environment. In other words, the method of adsorption with functionalized CNTs + DESs proved to be the most suitable. The practical diagnostics and conclusions generated from this research should prove valuable to engineers and environmental scientists involved in carbon nanotube applications in environmental remediation.

Humic acid-nanoceria composite as a sustainable adsorbent for simultaneous removal of uranium(VI), chromium(VI), and fluoride ions from aqueous solutions.

In this article, the multifunctional behavior of novel, efficient, and cost-effective humic acid-coated nanoceria (HA@CeO2 NPs) was utilized for the sorptive removal of U(VI), Cr(VI), and F- ions at different conditions. The production cost of HA@CeO2 was $19.28/kg and was well characterized by DLS, FESEM, HRTEM, FTIR, XRD, XPS, and TGA. Batch adsorption study for U(VI) (at pH ~ 8), Cr(VI) (at pH ~ 1), and F- (at pH ~ 2) revealed that the maximum percentage of sorption was > 80% for all the cases. From the contact time experiment, it was concluded that pseudo-second-order kinetics followed, and hence, the process should be a chemisorption. The adsorption study revealed that U(VI) and Cr(VI) followed the Freundlich isotherm, whereas F- followed the Langmuir isotherm. Maximum adsorption capacity for F- was 96mgg-1. Experiments in real water suggest that adsorption is decreased in Kaljani River water (~ 12% for Cr(VI) and ~ 11% for F-) and Kochbihar Lake water (25.04% for Cr(VI) and 20.5% for F-) because of competing ion effect. Mechanism was well established by the kinetic study as well as XPS analysis. Because of high adsorption efficiency, HA@CeO2 NPs can be used for the removal of other harmful water contaminants to make healthy aquatic life as well as purified drinking water.

High performance of reduced graphene oxide and g-C3N4 co-doped CuFe2O4 for peroxymonosulfate activation under visible light: Degradation process of sulfamethazine via a singlet oxygen dominated pathway

Peroxymonosulfate (PMS) activation by heterogeneous metal-based catalysts has been extensively applied for the degradation of organic pollutants in water. However, the catalysts suffer from the low oxidant utilization efficiency, pH limitations and severe matrix interference. Here, a reduced graphene oxide and g-C3N4 co-doped copper ferrite (rGO-CNCF) was synthesized and its performance for PMS activation under visible light was evaluated for removal of sulfamethazine. In the condition of rGO-CNCF (0.2 g/L) and PMS (0.1 g/L), the vis/rGO-CNCF/PMS system could degrade 99.9 % of sulfamethazine (SMT, 10 mg/L) within 30 min at pH 7.0, and the system also showed high degrading abilty of SMT over a wide pH range (0–14), along with a good adaptability to common coexisting ions in water solution. The introduction of rGO not only enhanced the stability of rGO-CNCF but also changed the binding sites between PMS and rGO-CNCF which reduced the adsorption energy. Singlet oxygen (1O2) was unveiled to be the major reactive oxygen species (ROS), which was produced by the transformation between negatively charged PMS (HSO5−) and water,along with the self-degradation of PMS. SMT was decomposed through four degradation pathways in this system, and quantitative structure–activity relationship (QSAR) predictions indicated a significant decrease in its toxicity. Results of this study indicated that the material can efficiently activate persulfate for the removal of organic pollutants from water under visible light conditions and it provided a novel catalytic system for removal of organic contaminants in water.

Sustainable Zeolite–Silver Nanocomposites via Green Methods for Water Contaminant Mitigation and Modeling Approaches

This study explores cutting-edge and sustainable green methodologies and technologies for the synthesis of functional nanomaterials, with a specific focus on the removal of water contaminants and the application of kinetic adsorption models. Our research adopts a conscientious approach to environmental stewardship by synergistically employing eco-friendly silver nanoparticles, synthesized using Justicia spicigera extract as a biogenic reducing agent, in conjunction with Mexican zeolite to enhance contaminant remediation, particularly targeting Cu2+ ions. Structural analysis, utilizing X-ray diffraction (XRD) and high-resolution scanning and transmission electron microscopy (TEM and SEM), yields crucial insights into nanocomposite structure and morphology. Rigorous linear and non-linear kinetic models, encompassing pseudo-first order, pseudo-second order, Freundlich, and Langmuir, are employed to elucidate the kinetics and equilibrium behaviors of adsorption. The results underscore the remarkable efficiency of the Zeolite–Ag composite in Cu2+ ion removal, surpassing traditional materials and achieving an impressive adsorption rate of 98% for Cu. Furthermore, the Zeolite–Ag composite exhibits maximum adsorption times of 480 min. In the computational analysis, an initial mechanism for Cu2+ adsorption on zeolites is identified. The process involves rapid adsorption onto the surface of the Zeolite–Ag NP composite, followed by a gradual diffusion of ions into the cavities within the zeolite structure. Upon reaching equilibrium, a substantial reduction in copper ion concentration in the solution signifies successful removal. This research represents a noteworthy stride in sustainable contaminant removal, aligning with eco-friendly practices and supporting the potential integration of this technology into environmental applications. Consequently, it presents a promising solution for eco-conscious contaminant remediation, emphasizing the utilization of green methodologies and sustainable technologies in the development of functional nanomaterials.

Engineering Magnetic Biochar from Polyphenol-Functionalized Biomass for the Removal of Broad-Spectrum Water Contaminants

Engineering Magnetic Biochar from Polyphenol-Functionalized Biomass for the Removal of Broad-Spectrum Water Contaminants

Theory-guided unraveling of the mechanism underlying Cu1.0/Mn1.0-ZnO with dual reaction centers for enhanced peroxymonosulfate activation

Developing efficient catalytic systems for water contamination removal is a topic of great interest. However, the use of heterogeneous catalysts faces challenges due to insufficient active sites and electron cycling. In this study, results from first-principles calculations demonstrate that dual reaction centers (DRCs) are produced around the Cu and Mn sites in Cu1.0/Mn1.0-ZnO due to the electronegativity difference. Experimental results reveal the material with DRCs greatly enhances electron transfer efficiency and significantly impacts the oxidation and reduction of peroxymonosulfate (PMS). In addition, the self-consistent potential correction (SCPC) method was introduced to correct the energy and charge of charged periodic systems simulating a catalytic process, resulting in more precise catalytic results. Specifically, the material exhibits a preference for adsorbing negatively charged PMS anions at electron-deficient Mn sites, facilitating PMS oxidation for the generation of 1O2, and PMS reduction around the electron-rich Cu for the formation of •OH and SO4•−. The major reactive oxygen species is 1O2, showcasing effective performance in various degradation systems. Overall, our work provides novel insights into the persulfate-based heterogeneous catalytic oxidation process, paving the way for the development of high-performance catalytic systems for water purification.

Baked hydrogel from palm starch and modified chitosan for water contaminant removal

Baked hydrogel from palm starch and modified chitosan for water contaminant removal

Textile waste valorization as potential activated carbon precursor for the removal of water contaminants: Commentary

Textile waste has become a global concern as its generation is increasing at an alarming rate. Various ways to manage and reduce textile waste are currently being sought, including reutilization and conversion into value-added products, to diversify its usage in an effort to minimize its environmental impact. Recent trends have shown the potential of textile waste as low-cost adsorbent for wastewater treatment applications. This paper aims to highlight the activation methods to convert textile waste into activated carbon and discuss its textural characteristics and performance in water contaminants removal. Data from literature showed promising high adsorption capacities of heavy metals, dyes, and pharmaceuticals by textile waste-derived activated carbons. Overall, the valorization of textile waste into activated carbon is generally feasible. Also, the superior surface chemistry and textural properties are imperative towards the exceptional performance of textile waste activated carbon in wastewater treatment applications.

Eco-synthesis, characterization and application of waste plastics pyrolysis char in arsenic removal from contaminated water: An integrated circular framework with parametric response surface methodology optimization-cum-artificial neural network model

Eco-synthesis of a novel, cost-effective activated adsorbent from waste low-density polyethylene plastic pyrolysis char at 550 °C and its arsenic adsorption potential in simulated aqueous media has been investigated. Characterization reveals good surface chemistry and evolved morphology of activated char adsorbent with carbon structures at high pyrolysis temperature, thereby facilitating high arsenic adsorption uptake. A unique integrated framework of kinetic equilibrium investigation, parametric optimization applying response surface methodology (RSM) with responsive arsenic adsorption efficiency and artificial neural network (ANN) model for response validation has been presented. There is reasonably good fitting of experimental equilibrium figures into the Langmuir isotherm model (R2 = 0.9920). The effects of adsorbent pyrochar dose, arsenic concentration, contact time and pH on the arsenic removal capacity have been depicted via conjugate RSM graphs. The ANN regression curves showed R2 value of 0.99436, validating the model with ANN architecture as 4–8-1. Iron oxide complexation with arsenic on adsorbent surface is reported to play a dominant role in the proposed adsorption mechanism. The proposed hybridized model can be applied to examine the adsorptive removal of various contaminants in water. Techno-economic analysis of scaled-up community arsenic filter showed high removal efficiency (> 90%) of arsenic by activated plastic pyro-char adsorbent from contaminated water at an affordable cost of 0.67 $/m3 of treated water. The activated plastic waste pyro-char with an adsorption capacity of 7.21 mg/g is, therefore, environmentally sustainable in plastic waste management in the post-pandemic era for a ‘waste to wealth’ circular economy with perspective arsenic removal from contaminated water.

Fabrication of novel Ag3PO4/LiFe5O8 nanocomposites for dual applications in sustainable photocatalytic removal of harmful antibiotics and ratiometric electrochemical detection of hazardous carbendazim insecticide

Herein, for the first time bi-functional magnetic nanocomposites based on Ag3PO4 (SP) and LiFe5O8 (LF) were prepared with different ratio of LF (xLFSP, x = 2.5, 5, 10, 15 and 20 wt% of LF) and synergy between the individual components of the nanocomposite were studied for dual applications. Different analytical techniques were employed to examine the physicochemical features of the synthesized materials. In the presence of H2O2 and visible light, 10LFSP nanocomposite possess superior photocatalytic activity towards levofloxacin (LFX, 98% removal) and tetracycline (TC, 95% removal) drugs. Further, 10LFSP was employed to modify a glassy carbon electrode (GCE) and fabricate a ratiometric electrochemical sensor for the detection of the pernicious insecticide carbendazim (CBM). Under optimized conditions, ratiometric signal is linear to the CBM concentration in the range of 0.05 to 10 μM with a detection limit of 20 nM. Moreover, the proposed sensor 10LFSP/GCE was successfully validated in the detection of CBM in real water samples. Thus, the present work provides a venue for the design of multifunctional nanomaterial that could solve the dual purpose of detection and removal of water contaminants.

Investigation of Calcination Duration on the Surface Morphology and Specific Surface Area of Zeolite-Chitosan Composite with Oil Palm Ash for Potential Water Contaminant Remediation

This research investigates how varying calcination durations affect the surface characteristics of a Zeolite-Chitosan composite with oil palm ash, aiming to determine its water contaminant removal potential. Three different calcination durations (1, 2, and 3 hours) are studied. The synthesis involves mixing oil palm ash with Zeolite-Chitosan, followed by varying-duration calcination. Scanning electron microscopy (SEM) and surface area analysis (SAA) are used to assess surface characteristics. Initial findings indicate that changing calcination duration significantly impacts the composite’s surface features and specific surface area. Longer calcination leads to increased surface roughness and higher specific surface area. The 3-hour calcination results in the highest surface roughness and specific surface area among the durations tested. These findings suggest that calcination duration is crucial in altering the composite’s structural properties, which could affect its efficacy in adsorbing water contaminants. Ongoing research aims to better understand the relationship between calcination duration and the composite’s adsorption performance, ultimately optimizing the synthesis of the Zeolite-Chitosan composite with oil palm ash for efficient water contaminant remediation.

Study on the biodegradation of phenol by Alcaligenes faecalis JH1 immobilized in rice husk biochar

Immobilized microbial technology is a sustainable solution to reduce water pollution. Understanding the microorganisms in immobilized biochar is critical for the removal of contaminants in water. Biochar as a carrier of microorganisms, there are some problems need to be focused on, microporous structure blockage limiting the contact between microorganisms and pollutants for further degradation, unstable microbial loading, and low cycle times. To solve these problems, Alcaligenes faecalis was immobilized with rice hull biochar to study its adsorption and degradation characteristics of phenol. It was found that A. faecalis JH1 could effectively remove 300 mg/L of phenol within 24 h. The adsorption capacity of rice husk biochar for phenol increased with the increasing pyrolysis temperature (700 &amp;gt; 500&amp;gt;300°C). The immobilized biomass of JH1 from 700°C rice husk biochar reached 249.45 nmol P/g at 24 h of fixation reaction. It was found that the phenol removal rate of JH1 immobilized at all temperature biochar reached 300 mg/L within 12 h after the sixth cycle. As the number of cycles increased, bacteria grew and adhered to the biochar, forming a thick viscous biofilm and accelerating the removal of phenol. The results showed that A. faecalis could firmly adhere to rice hull biochar and degrade phenol effectively, with good durability and cyclicity.

Photothermal porphyrin-based covalent organic framework for efficient removal of perfluoroalkyl substances

Temperature is vital to the removal ability of adsorbent materials. The application of convenient and energy-efficient light-induced heating to promote the removal of emerging contaminants is rarely reported. Here, we report synthesis of a photothermal porphyrin-based covalent organic framework (COF) called Por-MA for efficient removal of perfluoroalkyl substances (PFASs) in environment water. The crystalline Por-MA with rich nitrogen and ordered structure can provide electrostatic and hydrogen bonding interactions for adsorption of PFASs, further give a large adsorption capacity (686.6 mg g−1) and rapid adsorption kinetics (equilibrium time < 10 min) for perfluorooctanoic acid (PFOA) at 25 °C, outperforming several other COF-based sorbents. Moreover, endothermic adsorption of PFOA on Por-MA made promoting adsorption of PFASs on photothermal Por-MA with facile illumination possible. Removal efficiencies of PFASs on Por-MA in environmental water samples also significantly improved with LED irradiation, indicating the high potential of photothermal COFs for removal of contaminants in practical water.

A New Two-Parameter Isotherm for Modeling Adsorptive Removal of Water Contaminants

A New Two-Parameter Isotherm for Modeling Adsorptive Removal of Water Contaminants

Modulatory effect of magnesium hydroxide-nanoparticles on lead-induced toxicity in river Clarias gariepinus near mining site

Effluents emerging from unprotected local mining activities pollute the nearby rivers containing aquatic lives. Advent of nanotechnology however, supposedly helps in removal of water contaminants and as well make waste water remediation possible. To this effect, Clarias gariepinus from rivers near mining site at Ijero-Ekiti, Ekiti-State, Nigeria were collected and exposed to 62.5, 125 and 250mg/L suspension of 10nm magnesium hydroxide nanoparticles (MgOHNPs) for 14-days under semi-static conditions. The suspected lead concentration in the river water was estimated using atomic absorption spectrophotometer while the quality of the river water was also examined. Clarias gariepinus collected were sacrificed and alterations in their biochemical and hematological indices were evaluated. The results showed that water sample from river I exhibit highest (0.033ppm) lead concentration while water sample from river III has the lowest (0.006ppm) lead concentration relative to their proximity to the mining site. Besides, the collected fishes demonstrated significant (P&lt;0.05) concentration dependent increase in some biochemical indices and no observable significant alteration in hematologic state of the fishes at tested doses. Hence, results from this study suggest that toxic lead effluent from local mining activities may have elevated lead concentration levels in nearby rivers while exposure to MgOHNPs could evoke alterations in physiological system of the inhabiting aquatic lives.

Adsorptive Recovery of Heavy Metal Ions from Aquatic Systems Using Metal‐Organic Frameworks: A Perspective in the Sustainable Development of Nanomaterials

AbstractRapid industrialization in the developing countries has facilitated the unwanted mixing of wastes into the already depleting sources of potable, domestic and industrial water. In particular, the mixing of toxic heavy metal wastes into the aquatic resources have not only increased the scarcity of water at the different levels of usage but also hygiene of the ecosystem is further threatened by the presence of abysmal quality of aquatic environment around the living world. Thus, it has become quite imperative to mitigate such problems through the removal of such water contaminants at the sources before supplied for a specific purpose. In this direction, among the other available mass transfer techniques, specific and efficient adsorption of heavy metal species on the nanomaterials such as metal‐organic frameworks (MOFs) are found to be a promising method of heavy metal ions recovery. This reports targets to provide a new perspective into heavy metal ions removal from wastewater as a rationale for sustainable nanomaterial engineering through the recycling of toxic metal species as precious precursors in the synthesis of nanomaterials. Decades of exploring materials sciences led to the generation of groundbreaking materials of nanoscale regime, which has advanced myriad avenues of science and technology, viz. electronic, energy, biomedical, environmental, agriculture applications, and more. In this regard, nanotechnology has had a global impact by several folds, which can be observed in all day‐to‐day facilities. This perspective aims to conceptualize a strategy of wastewater decontamination through the adsorptive retrieval of heavy metal species to be subsequently recycled in the design of smart nanomaterials.

Removal of Phosphorus and Cadmium from Wastewaters by Periphytic Biofilm

Phosphorus (Pi) and cadmium (Cd) contamination in water sources pose significant health risks and environmental concerns. Periphytic biofilms have been recognized for their ability to effectively remove these contaminants from aquatic environments. This study aimed to investigate the impact of photon and electron treatments on Pi and Cd removal by periphytic biofilms. The experiments spanned a monthly timeframe, focusing on how photon and electron treatments affected the contaminant removal efficiency of periphytic biofilms. The results revealed that while the introduction of electrons had a minimal impact on contaminant accumulation, the enhancement of photon exposure significantly improved the absorption capacity of periphytic biofilms. This, in turn, led to enhanced removal of Pi and Cd from the water. One possible explanation for this phenomenon is that photons played a crucial role in inducing nitrate and ammonium conversion, thereby facilitating the accumulation of 4.70 mg kg−1 Pi and 2.40 mg kg−1 Cd in periphytic biofilms. In contrast, electron treatment had limited effects on nitrate conversion. These findings provide valuable insights into the mechanisms underlying the removal of water contaminants by periphytic biofilms under the influence of electron and photon treatments. Furthermore, they have practical implications for improving pollutant removal capabilities in aquatic ecosystems using periphytic biofilms.

Mechanism insights into photo–assisted peroxymonosulfate activation on oxygen vacancy–enriched nolanites via an electron transfer regime

The utilization of photo–assisted persulfate activation for the removal of organic contaminants in water has garnered significant research interest in recent times. However, there remains a lack of clarity regarding specific contributions of light irradiation and catalyst structure in this process. Herein, a photo–assisted peroxymonosulfate (PMS) activation system is designed for the highly efficient degradation of organic contaminants on oxygen vacancy–enriched nolanites (Vo–FVO). Results suggest that the degradation of bisphenol A (BPA) in this system is a nonradical–dominated process via an electron transfer regime, in which VO improves the local electron density and thus facilitates the electron shuttling between BPA and PMS. During BPA degradation, PMS adsorbed at the surface of FVO–180 withdraws electrons near VO and forms FVO–PMS* complexes. Upon light irradiation, photoelectrons effectively restore the electron density around VO, thereby enabling a sustainable electron transfer for the highly efficient degradation of BPA. Overall, this work provides new insights into the mechanism of persulfate activation based on defects engineering in nolanite minerals.