Removal Of Specific Pollutants Research Articles

Development of a Novel Cyclodextrin-Chitosan Polymer for an Efficient Removal of Pharmaceutical Contaminants in Aqueous Solution.

A novel polymer synthesized by grafting three cyclodextrins onto chitosan was characterized and evaluated for its potential to adsorb two pharmaceutical residues: ibuprofen and progesterone. The influence of various operational parameters, including contact time, initial molecule concentration, pH, ionic strength, and temperature, was investigated. The synthesized polymer exhibits an amorphous and porous structure with a remarkable swelling capacity of 9.5 mmol/g. It demonstrates remarkable adsorption capacities for progesterone and ibuprofen, reaching 90% and 75%, respectively. Kinetic studies reveal that the adsorption of both molecules follows a pseudo-second-order model. A DSC analysis elucidated the adsorption mechanism, which is governed by the formation of inclusion complexes and electrostatic interactions within the polymer network. The polymer's regeneration after 23 cycles demonstrates its sustainable adsorption efficiency. The combination of chitosan with three cyclodextrins opens up promising new avenues for water treatment and the removal of specific pollutants. This approach significantly improves the material's selectivity towards target pollutants, offering a significant advantage in pollution remediation applications.

Axially coordinated dual-atomic-site catalysts for nearly 100% peroxymonosulfate conversion to 1O2 in membrane filtration

Reactive membrane filtration, integrating membrane technology with catalytic processes, offers a promising avenue for efficiently generating and utilizing active species in environmental remediation. Herein, a dual-atom Co-Mn site achieved through axial coordination on N-doped graphene catalyst (sp-CoMn@NG) has been developed and applied in membrane filtration for the targeted removal of specific pollutants. Experimental investigations, alongside density functional theory (DFT) calculations, have substantiated that axial coordination can effectively reduce the adsorption energy and activation barrier of PMS, thereby facilitating nearly 100% conversion of PMS to 1O2 and enhancing catalytic performance. Mechanistic studies further elucidate the 1O2 production mechanism through a superoxide-mediated chain reaction at the axially coordinated Co-Mn center, as well as the inactivation mechanism of catalytic membranes via the addition reaction of 1O2 and phenolic-hydroxyl compounds. This research underscores the intelligent prefabrication of axial coordination in dual-atomic-site catalysts, offering an efficient approach for scalable 1O2 production in reactive membrane filtration.

Selective capture of palladium from acid wastewater by thiazole-modified activated carbon: Performance and mechanism

As a kind of scarce metal, palladium is widely used in many chemical industries. It essential to recover palladium from secondary resources, especially acidic media, owing to high content of palladium in secondary wastes and widespread extraction of palladium via strong acids. Chemically modified carbon materials not only have the advantage of activated carbon but also achieve the precise removal of specific pollutants, which is a kind of adsorption material with broad application prospects. In this direction, we report a solid carbon material named AT-C, which is obtained by one-step synthesis of 2-aminothiazoles grafted to the carbon surface by amidation. The present adsorbent delivers a high palladium adsorption capacity of 178.9 mg g−1, and desirable thermal and chemical stability. The uniform presence of abundant sulfur atoms and CO in the porous network enables AT-C to achieve selective absorption and rapid adsorption kinetics of Pd2+ in the complex water mixture containing many competing ions in the acidic pH range. For the strongly acidic leachates of catalysts, AT-C exhibits outstanding stability in cyclic experiments. Meanwhile, the fixed-bed column test indicates that 1076 bed volumes of the feeding streams can be effectively treated. In addition, AT-C exhibits superior adsorption selectivity, and the recovery efficiency of Pd2+ in actual industrial wastewater is 96.6%. This work realizes an efficient, rapid, and selective removal of palladium under acidic conditions, and provides a reference for complex industrial water treatment and resource recovery of precious metals.

Recent Development and Environmental Applications of Nanocellulose-Based Membranes.

Extensive research and development in the production of nanocellulose production, a green, bio-based, and renewable biomaterial has paved the way for the development of advanced functional materials for a multitude of applications. From a membrane technology perspective, the exceptional mechanical strength, high crystallinity, tunable surface chemistry, and anti-fouling behavior of nanocellulose, manifested from its structural and nanodimensional properties are particularly attractive. Thus, an opportunity has emerged to exploit these features to develop nanocellulose-based membranes for environmental applications. This review provides insights into the prospect of nanocellulose as a matrix or as an additive to enhance membrane performance in water filtration, environmental remediation, and the development of pollutant sensors and energy devices, focusing on the most recent progress from 2017 to 2022. A brief overview of the strategies to tailor the nanocellulose surface chemistry for the effective removal of specific pollutants and nanocellulose-based membrane fabrication approaches are also presented. The major challenges and future directions associated with the environmental applications of nanocellulose-based membranes are put into perspective, with primary emphasis on advanced multifunctional membranes.

Enhanced orientation photocatalytic ability of 1D inorganic imprinted oxygen vacancy CdO0.5S0.5 by confining the target to the specific reaction sites enriched in electrons

The conventional means for selectively capturing and subsequently degrading specific organic pollutants entails the development of an inorganic imprinted photocatalytic material with visible light response, high activity, and high stability. Hence, the inorganic imprinted oxygen vacancy CdO0.5S0.5 (II-OV-CdO0.5S0.5) was prepared by S2- ion exchange assisted inorganic imprinting technology. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and thermogravimetry analysis (TGA) were used to comprehensively prove that S element only permeated the surface of the material, and there were imprinted cavities and a few oxygen defects caused by inorganic imprinting. Photoelectrochemistry experiments and DFT theoretical calculation showed that the electrons gathered near the oxygen defects around the imprinted cavities (specific reaction sites), and the reactive center formed was more favorable to the specific adsorption of tetracycline (TC). Since TC was confined to the specific reaction sites enriched in electrons, the apparent rate constant of II-OV-CdO0.5S0.5 (0.0220 min−1) was 2.18 times that of CdO0.5S0.5 (0.0101 min−1) after TC photodegradation for 60 min under visible light. More importantly, although the space size of ciprofloxacin (CIP) was smaller than that of TC, because the imprinted cavities not only had a size effect, but also possessed the specific adsorption sites, there was no significant enhancement in the degradation of CIP. Therefore, II-OV-CdO0.5S0.5 demonstrated excellent orientation photocatalytic ability for the target (TC), under the premise of improving the photodegradation of the target, II-OV-CdO0.5S0.5 effectively inhibited the photodegradation of other reference pollutants. This work provides an exemplary method for the design of functionalized photocatalytic materials and the orientation removal of specific pollutants.

Nanocellulose-Based Materials for Water Treatment: Adsorption, Photocatalytic Degradation, Disinfection, Antifouling, and Nanofiltration.

Nanocelluloses are promising bio-nano-materials for use as water treatment materials in environmental protection and remediation. Over the past decades, they have been integrated via novel nanoengineering approaches for water treatment processes. This review aims at giving an overview of nanocellulose requirements concerning emerging nanotechnologies of waster treatments and purification, i.e., adsorption, absorption, flocculation, photocatalytic degradation, disinfection, antifouling, ultrafiltration, nanofiltration, and reverse osmosis. Firstly, the nanocellulose synthesis methods (mechanical, physical, chemical, and biological), unique properties (sizes, geometries, and surface chemistry) were presented and their use for capturing and removal of wastewater pollutants was explained. Secondly, different chemical modification approaches surface functionalization (with functional groups, polymers, and nanoparticles) for enhancing the surface chemistry of the nanocellulose for enabling the effective removal of specific pollutants (suspended particles, microorganisms, hazardous metals ions, organic dyes, drugs, pesticides fertilizers, and oils) were highlighted. Thirdly, new fabrication approaches (solution casting, thermal treatment, electrospinning, 3D printing) that integrated nanocelluloses (spherical nanoparticles, nanowhiskers, nanofibers) to produce water treatment materials (individual composite nanoparticles, hydrogels, aerogels, sponges, membranes, and nanopapers) were covered. Finally, the major challenges and future perspectives concerning the applications of nanocellulose based materials in water treatment and purification were highlighted.

Dyeing and finishing wastewater treatment in China: State of the art and perspective

China has the largest textile production and export in the world, with a massive amount of wastewater and related pollutants releasing. With an increasing concern to improve water quality, dyeing and finishing wastewater (DFW) requires better disposal or reclamation. In this review, the characteristics of wastewater in different natural and synthetic fiber production processes as well as the origins of their specific pollutants such as aniline, absorbable organic halogens (AOX), sulfide, hexavalent chromium and antimony were summarized. The discharge standards for DFW in China, have undergone complex evolution processes, which were discussed including the current standard, the revision detail and the one to be implemented. Furthermore, the current status of pollutant reduction in the textile industry, covering cleaner production and wastewater treatment, was targeted, in particular the state of the art of specific pollutant removal technologies and their feasibility of application for DFW treatment. Also, reclamation systems based on wastewater discharge characteristics and reclaimed water quality requirements were reviewed. Overall, the systematic solution of source reduction of wastewater and contaminants, coupled with subsequent treatment and recycling, is crucial for the sustainable development of the textile industry.

Applications of Up-Flow Anaerobic Sludge Blanket (UASB) and Characteristics of Its Microbial Community: A Review of Bibliometric Trend and Recent Findings.

The interest in research on up-flow anaerobic sludge blanket (UASB) reactors is growing. The meta-analysis of bibliometric data highlighted the growing interest in four diverse topics: (i) energy recovery production; (ii) combination with other treatments; (iii) the study of processes for the removal of specific pollutants and, (iv) characterization of microbial community and granular sludge composition. In particular, the papers published in the first 6 months of 2021 on this process were selected and critically reviewed to highlight and discuss the results, the gaps in the literature and possible ideas for future research. Although the state of research on UASB is to be considered advanced, there are still several points that will be developed in future research such as the consolidation of the results obtained on a semi-industrial or real scale, the use of real matrices instead of synthetic ones and a more in-depth study of the effect of substances such as antibiotics on the microbiota and microbiome of UASB granular biomass. To date, few and conflicting data about the environmental footprint of UASB are available and therefore other studies on this topic are strongly suggested.

An Eu-doped Zr-metal-organic framework for simultaneous detection and removal of antibiotic tetracycline

Due to the widespread use of tetracycline (TC), there is an increasing demand for rapid detection as well as effective removal of residual tetracycline for environment and food safety. Herein, we report an Eu/Zr-MOF material that combines the high adsorption performance of water-stable Zr-MOF and the unique emission characteristics of Eu3+, which enables both sensing and adsorption functions for TC. Eu/Zr-MOF can be achieved facilely by doping Eu3+ into Zr-MOF via the traditional hydrothermal method. In aqueous medium, the Eu3+ preferentially coordinate with TC molecules, which in turn acts as an antenna for UV–Vis absorbance to enhance the characteristic fluorescence of Eu3+. In such way, TC can be specifically detected in a wide dynamic range (0.001–0.5 µg/mL) with a low detection limit (0.00092 µg/mL). Moreover, by taking advantage of the unsaturated character of ZrO centers, the Eu/Zr-MOF has a TC loading capacity as high as 289 mg g-1. As a consequence, based on the Eu/Zr-MOF, rapid detection and efficient removal of TC from food and environment was realized at once. The principle of design proposed in this work may find more applications to synthesize new platforms for simultaneous sensing and removal of specific pollutants.

Establishing the Order of Importance Factor Based on Optimization of Conditions in PAHs Biodegradation

In environmental study, optimization of different factors is crucial to obtain high removal of specific pollutants. The sequence of important factors that were considered in optimization studies is less concerned, and this part is crucial before proceeding to full-scale bioremediation study. This study focuses on bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil with the potential bacteria, Corynebacterium urealyticum which is isolated from municipal sludge. The bacterial strain has evaluated the effectiveness of PAHs degradation at various factors on soil pH, soil temperature, initial PAHs concentration, initial bacteria number, and heavy metals concentration. The optimum condition for phenanthrene biodegradation was pH 7, 30 °C, 500 mg/kg of phenanthrene concentration, 109 cells/g soil, and without the addition of Zn. In establishing the ranking, we attempt to use a simple method based on the analysis of p values. Based on the analysis of degradation rates, the initial phenanthrene concentration shows the lowest p value, which means that it shows the highest ranking; the most significant factor to achieve highest degradation. In vice versa, the soil pH shows the highest ranking based on the analysis of bacteria growth rates, which is a very limited study that focuses on growth rates in the optimization study. The establishment of these rankings may reduce time, energy and cost in pilot or field study and at the same time achieve highest degradation in bioremediation work. Thus, it is highly recommended to develop the ranking before proceeding to design work in pilot and field study.

Precisely Controlled Multidimensional Covalent Frameworks: Polymerization of Supramolecular Colloids

AbstractRapid and selective removal of micropollutants from water is important for the reuse of water resources. Despite hollow frameworks with specific functionalized porous walls for the selective adsorption based on a series of interactions, tailoring a stable shape of nanometer‐ and micrometer‐sized architectures for the removal of specific pollutants remains a challenge. Here, exactly controlled sheets, tubes, and spherical frameworks were presented from the crosslinking of supramolecular colloids in polar solvents. The frameworks strongly depended on the architecture of original supramolecular colloids. As the entropy of colloids increased, the initial laminar framework rolled up into hollow tubules, and then further curled into hollow spheres. These shape‐persistent frameworks showed unprecedented selectivity as well as specific recognition for the shape of pollutants, thus contributing to efficient pollutant separation.

Precisely Controlled Multidimensional Covalent Frameworks: Polymerization of Supramolecular Colloids

Rapid and selective removal of micropollutants from water is important for the reuse of water resources. Despite hollow frameworks with specific functionalized porous walls for the selective adsorption based on a series of interactions, tailoring a stable shape of nanometer- and micrometer-sized architectures for the removal of specific pollutants remains a challenge. Here, exactly controlled sheets, tubes, and spherical frameworks were presented from the crosslinking of supramolecular colloids in polar solvents. The frameworks strongly depended on the architecture of original supramolecular colloids. As the entropy of colloids increased, the initial laminar framework rolled up into hollow tubules, and then further curled into hollow spheres. These shape-persistent frameworks showed unprecedented selectivity as well as specific recognition for the shape of pollutants, thus contributing to efficient pollutant separation.

Kinetic and Prediction Modeling Studies of Organic Pollutants Removal from Municipal Wastewater using Moringa oleifera Biomass as a Coagulant

This study investigated the potential of Moringa oleifera (MO) seed biomass as a coagulant for the removal of turbidity, biochemical oxygen demand (BOD), and chemical oxygen demand (COD) of municipal wastewater. Triplicated laboratory experiments using MO coagulant added at varying treatment dosages of 50, 100, 150, 200 mg/L, and a control (0 mg/L) treatment were performed for a settling period of 250 min at room temperature. Kinetics and prediction variables of cumulative turbidity, BOD, and COD removal were estimated using simplified first order and modified Gompertz models. Results showed that the maximum removal of turbidity, BOD, and COD were 94.44%, 68.72%, and 57.61%, respectively, using an MO dose of 150 mg/L. Various kinetic parameters, such as rate constant (r), measured (REm) versus predicted (REp) cumulative removal, and specific pollutant removal rate (µm), were also maximum when an MO dose of 150 mg/L was added, the standard error being below 5%. The developed models were successfully validated over multiple observations. This study suggests low cost and sustainable removal of turbidity, BOD, and COD of municipal wastewater using MO seed biomass as a coagulant.

Mixture of different Pseudomonas aeruginosa SD-1 strains in the efficient bioaugmentation for synthetic livestock wastewater treatment

Strains selection for inoculation is the key to the successful construction of a bioaugmentation system, a promising strategy for specific pollutant removal. Pseudomonas aeruginosa SD-1 wild-type (WT) strain exhibited high capacity for biofilm formation but low efficiency for nitrate (NO3−) removal. Meanwhile, quorum sensing deficient strain ΔlasR showed excellent efficiency for NO3− removal but poor capability for colonization in activated sludge. The opposite effect of biofilm formation and NO3− removal exist in WT or ΔlasR, which limits the construction of bioaugmentation system of strain SD-1 and its application. To solve this issue, a mixture of WT and ΔlasR (v/v = 1:1) was used to construct a bioaugmentation system. Compared with the inoculation of WT or ΔlasR alone, the mixed inoculation not only was beneficial for activated sludge development but also for pollutant removal. The indicators for activated sludge including the abundance of P. aeruginosa, the sludge volume index and the average particle size in mixed inoculated reactors were close to those of reactors with single and repeated inoculation of WT. The effluent of chemical oxygen demand (COD) and NO3−-N were stable at 3.9–22.6 mg L−1 and 0–5.53 mg L−1 after d 3, respectively. This study presents a detailed case on the ecological tradeoff of colonization and pollutant removal of inoculated strains during bioaugmentation. The results provide information on the appropriate conditions for application of P. aeruginosa SD-1 for livestock wastewater treatment and further enrich our ecological understanding of bioaugmentation.

Compost Biofilters for Protection of Environmentally Sensitive Areas Receiving Roadway Runoff

Runoff from roads is well recognized as containing a host of heavy metals that may degrade water quality. This awareness has driven a focus towards management strategies intended to attenuate the transport of heavy metals to nearby water bodies. Composted biomass has been shown to have the ability to retain common roadway runoff pollutants, leading to interest in its use as a filter material for the protection of environmentally sensitive areas. Compost biofilters can be constructed in a tubular geometry to intercept surface flow and can be amended with polymers for the targeted removal of specific pollutants. Addressing the need for validation of this concept under field conditions, commercially available tubular biofilters with three different polymeric amendments were studied to assess their efficiency in removing heavy metals and total suspended solids. The filters each contained a mixture of municipal compost and were installed in series as a treatment train adjacent to a busy section of highway 401 in southern Ontario, Canada. Untreated inflow concentrations of chromium, cadmium, copper and lead exceeded Ontario Provincial Water Quality Objectives (PWQO). The biofilter treatment train reduced chromium to below its PWQO, while copper remained above. Results demonstrate removal efficiencies for the treatment train ranging from 15.5% (nickel) to 93.6% (chromium). The low removal efficiency of nickel is attributed in part to its low inflow concentration. Each consecutive filter also reduced TSS concentrations, with an event mean removal efficiency of 50% for the treatment train as a whole.

An overview of heavy metal removal from wastewater using magnetotactic bacteria

AbstractConsidering the increase in water contamination by heavy metal discharge, water quality experts are focusing on innovative future technologies for wastewater treatment. There are a number of physical, chemical and biological processes for acquiring high‐quality effluents; however, these treatment technologies have shown some limitations regarding their specific pollutant removal efficiencies, vulnerability to environmental pollutants, higher cost and energy requirements, excessive sludge volume and toxicity issues. Therefore, this review/concept paper focuses on the application of magnetotactic bacteria (MTB) in the removal of heavy metal from wastewater and also proposes a model application of MTB‐based treatment process. The unique property of the MTB is to move along the periphery of the applied external magnetic fields due to nano sized magnetosomes (MS). MS are basically the biomineral crystals of either magnetite (Fe3O4) or greigite (Fe3S4) with a size range of 30–120 nm. Moreover, challenging aspects concerning MTB employment in the removal of heavy metal from wastewater also are discussed in detail for the consideration of experts who are involved in the development of new treatment technologies or for retrofications of existing processes. © 2018 Society of Chemical Industry

Synthesized af-PFCl and GG-g-P(AN)/TEOS hydrogel composite used in hybridized technique applied for AMD treatment

In the present study af-PFCl, GL-g-P(AN) hydrogel and GL-g-P(AN)/TEOS hydrogel composite were synthesized. The hydrogels were characterized using the fourier transformed infra-red (FTIR) and the scanning electron microscope (SEM) techniques. The coagulant af-PFCl and the hydrogels were applied consecutively in flocculation and adsorption processes respectively for the treatment of acid mine drainage (AMD). It was observed that the grafting process increased the amount of binding groups on the hydrogels. The hybridization of the techniques assisted in the removal of anions; while the cations were mostly removed by the adsorption process. The adsorbents behaviour was fittingly expressed by the pseudo-second order model. The adsorption capacities of GL-g-P(AN)/TEOS hydrogel composite for the removal of Al, As and Zn were 3.89, 0.66 and 0.394 respectively; while the adsorption capacities of GL-g-P(AN) for the removal of Al and Mg were 3.47 and 9.66 mg/g respectively.The techniques applied in this study have shown good potential for the removal of specific pollutants from the AMD; it is however, important that the appropriate hybridization of techniques allows to remove all the pollutants and restore acceptable water quality.

Evaluation of bioaugmentation using multiple life cycle assessment approaches: A case study of constructed wetland

Bioaugmentation is a promising technology to enhance the removal of specific pollutants; however, environmental impacts of implementing bioaugmentation have not been considered in most studies. Appropriate methodology is required for the evaluation from both in-depth and comprehensive perspectives, which leads to this study initiating the application of life cycle assessment (LCA) of bioaugmentation. Two LCA methods (CML and e-Balance) were applied to a bioaugmentation case with the aim of illustrating how to evaluate the environmental impacts of bioaugmentation from different perspectives based on the selection of different LCA methods. The results of the case study demonstrated that the LCA methods with different methodology emphasis produced different outcomes, which could lead to differentiated optimization strategies depending on the associated perspectives. Furthermore, three important aspects are discussed, including coverage of impact categories, the selection of characterization modeling for specific pollutants, and the requirement of including economic indicators for future investigation.

Performance and microbial community of a membrane bioreactor system — Treating wastewater from ethanol fermentation of food waste

In this study, a lab-scale biological anaerobic/anaerobic/anoxic/membrane bioreactor (A3-MBR) was designed to treat wastewater from the ethanol fermentation of food waste, a promising way for the disposal of food waste and reclamation of resources. The 454 pyrosequencing technique was used to investigate the composition of the microbial community in the treatment system. The system yielded a stable effluent concentration of chemical oxygen demand (202±23mg/L), total nitrogen (62.1±7.1mg/L), ammonia (0.3±0.13mg/L) and total phosphorus (8.3±0.9mg/L), and the reactors played different roles in specific pollutant removal. The exploration of the microbial community in the system revealed that: (1) the microbial diversity of anaerobic reactors A1 and A2, in which organic pollutants were massively degraded, was much higher than that in anoxic A3 and aerobic MBR; (2) although the community composition in each reactor was quite different, bacteria assigned to the classes Clostridia, Bacteroidia, and Synergistia were important and common microorganisms for organic pollutant degradation in the anaerobic units, and bacteria from Alphaproteobacteria and Betaproteobacteria were the dominant microbial population in A3 and MBR; (3) the taxon identification indicated that Arcobacter in the anaerobic reactors and Thauera in the anoxic reactor were two representative genera in the biological process. Our results proved that the biological A3-MBR process is an alternative technique for treating wastewater from food waste.

Removal of monochlorobenzene from air in a trickling biofilter at high loading rates

BACKGROUND: In this study, the biofiltration of air streams laden with monochlorobenzene (MCB) vapours was investigated using a trickling biofilter operated co-currently. The device was filled with ceramic material and inoculated with an acclimated microbial culture. A neutralization process was carried out in a separate unit using crushed oyster shells. Long-term biofilter performance was evaluated over a 10-month period of continuous experiments under different influent pollutant concentrations from 0.10 to 1.75 g m−3, sequentially stepped up through three different apparent air residence times of 60, 30, and 15 s. RESULTS: Pollutant removal was shown to be complete at influent concentrations up to 1.25, 0.75 and 0.20 g m−3, and apparent air residence times of 60, 30, and 15 s, respectively. The maximum elimination capacity was found to be 95.0 g mPM−3 h−1 for an influent concentration of 1.0 g m−3 and an apparent air residence time of 30 s, corresponding to a loading rate of 120.0 g mPM−3 h−1. Monochlorobenzene and biomass concentration profiles along the biofilter evidenced the dependence of microbial concentration distribution on the pollutant loading rate and the existence of a linear relationship between biomass concentration and specific pollutant removal rate, regardless of the operating conditions applied. A macrokinetic analysis shows that the MCB removal rate is zeroth order for low values of MCB concentration. A critical value of MCB concentration exists at all superficial air velocity at which the biomass growth is inhibited. A simple kinetic model is developed which is able to describe the inhibition behaviour under any operating conditions. CONCLUSION: The experimental results indicated that the system was effective and stable under various working conditions and over a long operating period, provided that the loading conditions corresponding to substrate inhibition of microbial growth are not exceeded. Copyright © 2012 Society of Chemical Industry