Water Remediation Research Articles

Evaluation of ZnO/NiO/kaolin nanocomposite as a sorbent/photocatalyst in hybrid water remediation process

Evaluation of ZnO/NiO/kaolin nanocomposite as a sorbent/photocatalyst in hybrid water remediation process

A Comprehensive Study of the Degradation of Veterinary Antibiotics by Non-Thermal Plasma: Computational, Experimental, and Biotoxicity Assessments

Water quality is threatened by numerous pollutants, among which antibiotics are of great concern due to their widespread use and unaltered excretion, leading to water contamination and fostering antibiotic resistance. To comprehensively address sustainable water remediation, herein, the susceptibility to non-thermal plasma degradation of two veterinary antibiotics (Oxytetracycline (OTC) and Lincomycin (LNC)) are compared in an integral approach, including computational analyses, plasma irradiation assays, and a byproduct toxicity assessment. The computational assessment was performed by evaluating the ionization potential (IP) obtained from Density Functional Theory calculations and determining the antibiotics’ susceptible sites for radical attack. Plasma irradiation achieved nearly complete degradation (~100%) of both compounds with the initial concentration of 1 mg L−1, while 60% degradation was observed when the starting concentration was 10 mg L−1. The mineralization rates were 21% and 31% for OTC and LNC, respectively. The degradation profiles followed similar trends, as expected from their comparable IP values. After treatment, the solution exhibited lower biotoxicity compared to the original antibiotics. Therefore, this work represents a step forward in addressing one of the key environmental challenges of our time and encourages further extending the analysis towards the remediation of water polluted with many other organic compounds.

Isolation and assessment of highly sucrose-tolerant yeast strains for honey processing factory's effluent treatment.

Wastewater from many food and beverage manufacturers is enriched in organic content, and it must therefore be treated before being discharged to comply with the strict environmental regulations to protect the final water quality. Concretely, the honey processing wastewater, that remains in holding tanks until is disposal, is a rich source of sugars and this high level of organic material will degrade the water quality if not treated properly provoking an imbalance in the ecosystem. There are different strategies for an adequate treatment of this wastewater effluent to obtain a sustainable usage. One of the techniques that is more cost-effective and environmental friendlier than chemical procedures used for water remediation, is the use of microorganisms (including algae, fungi, yeasts, or bacteria). Given that they are fast-growing, robust, and metabolically diverse, yeast strains are often used for wastewater treatment. In this work, we have studied the potential for bioremediation of non Saccharomyces yeast isolated from a honey processing wastewater generated by an Argentine exporting company. The inoculation of these yeast strains to the existing flora in the honey wastewater yielded a better improvement in the treatment yield. These results suggest that these strains display a promising role could for optimizing bioremediation strategies in industrial wastewater treatment processes.

Nitrifying bacteria for the remediation of organic nitrogen‐contaminated waters: a review

AbstractThe rapid growth of the world's population and its environmental impact has increased the demand for effective water treatment methods. Surface water systems, including rivers, streams, lakes, and ponds, have suffered contamination, leading to the urgent need for effective contaminant removal. Organic nitrogen compounds and nitrates are of particular concern because they pose risks to health and can cause environmental damage. However, traditional water‐treatment methods often prove ineffective for addressing these issues. For this reason, this research focuses on harnessing the capabilities of nitrifying bacteria to denitrify organic nitrogen compounds in water, exploring various bacterial strains, their functions, and their ability to obtain sources of carbon. The study also investigates innovative approaches such as biofilm systems, mixed cultures, and combined processes, which have shown stronger potential for nitrogen removal. Overall, it provides valuable insights into the use of nitrifying bacteria‐based technologies for water remediation in the face of growing environmental challenges.

Magnetic CuFe2O4 Nanoparticles Immobilized on Modified Rice Husk-Derived Zeolite for Chlorogenic Acid Adsorption

Adsorption has emerged as a promising method for removing polyphenols in water remediation. This work explores chlorogenic acid (CGA) adsorption on zeolite-based magnetic nanocomposites synthesized from rice husk waste. In particular, enhanced adsorbing materials were attained using a hydrothermal zeolite precursor (Z18) synthesized from rice husk and possessing a remarkable specific surface area (217.69 m2 g−1). A composite material was prepared by immobilizing magnetic copper ferrite on Z18 (Z18:CuFe2O4) to recover the zeolite adsorbent. In addition, Z18 was modified (Z18 M) with a mixture of 3-aminopropyltriethoxysilane (APTES) and trimethylchlorosilane (TMCS) to improve the affinity towards organic compounds in the final nanocomposite system (Z18 M:CuFe2O4). While the unmodified composite demonstrated inconsequential CGA removal rates, Z18 M:CuFe2O4 could adsorb 89.35% of CGA within the first hour of operation. Z18 M:CuFe2O4 showed no toxicity for seed germination and achieved a mass recovery of 85% (due to a saturation magnetization of 4.1 emu g−1) when an external magnetic field was applied. These results suggest that adsorbing magnetic nanocomposites are amenable to CGA polyphenol removal from wastewater. Furthermore, the reuse, revalorization, and conversion into value-added materials of agro-industrial waste may allow the opportunity to implement sustainability and work towards a circular economy.

Unveiling the potent Antimicrobial Photodynamic Therapy in Gram-positive and Gram-negative bacteria – Water remediation with monocharged chlorins

Water pollution is a significant concern worldwide, and it includes contaminants such as antibiotic-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) offers a non-invasive and non-toxic alternative for the inactivation of these microorganisms. So, this study reports the synthesis, structural characterisation, photophysical properties, and aPDT efficacy of cationic free-base and zinc(II) chlorin (Chl) derivatives bearing N,N-dimethylpyrrolydinium groups (H2Chl 1a and ZnChl 1b). The aPDT assays were performed against two bacterial models: Staphylococcus aureus (Gram-(+)) and Escherichia coli (Gram-(–)). The H2Chl 1a and ZnChl 1b distinct’s solubility profile, coupled with their ability to generate singlet oxygen (1O2) under light exposure, (H2Chl 1a, ФΔ = 0.58 <TPP, ФΔ = 0.65 < ZnChl 1b, ФΔ = 0.83) opens up their potential application as photosensitizers (PS) in aPDT. The effectiveness of H2Chl 1a and ZnChl 1b at 1.0 and 5.0 μM in aPDT against S. aureus and E. coli at 500 W.m–2 (total exposure time: 60 –120 min) showed a viability reduction > 6.0 log10 CFU.mL–1. Additionally, KI was used as a coadjuvant to potentiate the photoinactivation of E. coli, reaching the method’s detection limit (> 4.0 log10 RLU). As most of the PS developed to inactivate Gram-negative bacteria are cationic with three or more charges, the fact that the H2Chl 1a and ZnChl 1b with only one cationic charge photoinactivate E. coli at low concentrations and with a reduced light dose, it is an importing discovery that deserves further exploration. These monocharged chlorin dyes have the potential for water remediation.

Synthesis, characterisation of ZnO@PDA@Ag nanocomposite: Mechanistic interaction with BSA, photodegradation activity & in vitro cytotoxicity assay on H1299 lung cancer cell line

Despite advancements in diagnosis and therapeutic, cancer retains to be a greatest cause of fatality and economic damage to the world. Metallic nanoparticles have grabbed attention particularly in the field of medicine attributed to their noteworthy biological and catalytic properties, offering significant progress. The work aimed to create a novel biocompatible ‘Silver doped Polydopamine coated Zinc-Oxide nanocomposite’ and investigate its efficacy in treating H1299 lung cancer cells as well as water remediation. In this study, a ‘ZnO@PDA@Ag’ Nanocomposite was synthesised using co-precipitation method and was further characterised using DLS, FESEM-EDX, P-XRD, XPS, TEM and FT-IR techniques. The mechanistic interaction with blood protein, suggested strong binding interactions and notable structural changes in BSA upon exposure to the nanocomposite. The photocatalytic properties evaluated against the Rhodamine B Dye under UV–Visible light irradiation demonstrated a photodegradation of~49.77 % within 120 min for 60 μg/mL of the used nanocomposite. Herein, we present an evaluation of anticancer bioactivity of ZnO@PDA@Ag nanoparticles using MTT assay against the H1299 lung cancer cell line and its IC50 was estimated to be (42.42 ± 4) μg/mL. The cytotoxicity was enhanced through immobilization of Silver (Ag) metal on ZnO@PDA. Moreover, the hemolysis experiment was also conducted to demonstrate the biocompatibility of nanoparticle to human red blood cells. As a result, the successfully created biocompatible nanomaterial may be useful as an efficient drug-delivery system against cancer cells.

Recent development on neem (azadirachta indica) biomass absorbent: surface modifications and its applications in water remediation

This review paper discusses the latest advances in transfiguring Azadirachta indica (neem) biomass into an adsorbent and how it can be used to clean the environment. As an economical and environmentally favorable adsorbent material, neem biomass has become increasingly popular due to its bioactive properties and abundance. The review breaks down modification techniques into chemical and physical processes. Important physical changes covered include preactivation, carbonization, and using fluidized bed technologies and rotary kilns. It has been shown that these methods greatly improve the surface properties of neem biomass, which makes it better at absorbing things and holding more. The changes that were made also have an effect on the adsorption kinetics and isotherms, which helps us understand the adsorption rates and equilibrium behaviors of the changed adsorbents better. Neem biomass adsorbents are illustrated through their versatility and efficacy in the removal of organic pollutants, dyes, and heavy metals from effluent. This is illustrated through specific applications. Additionally, computational studies and artificial intelligence are looked into to see if they can help us understand how adsorption works at the molecular level, improve the efficiency of modification processes, and guess how adsorption will behave. The review also talks about the research gaps and suggests areas for future research. The review emphasizes the crucial importance of integrating experimental and computational methods to enhance the performance of the modified neem biomass and increase its environmental cleaning potential.

Enhancing carbamazepine degradation in electrochemical systems: The interplay of sulfur vacancies and absorbed peroxydisulfate in molybdenite electrodes

Achieving high reaction efficiency with low energy input is crucial for electrochemical water remediation processes, yet remains a significant challenge. This study reported a practicable method, utilizing natural molybdenite as particle electrodes in an electro-activated peroxydisulfate (PDS) process (3D system) to develop a cost-efficient electrocatalytic oxidation system. Molybdenite’s unique ability to generate sulfur vacancies during electrocatalysis significantly enhances system efficiency. The 3D system enhanced the rate constant of carbamazepine (CBZ) abatement sixfold compared to the system without molybdenite. Additionally, a substantial decrease in electrical energy per order (EE/O) from 7.13 kWh/m3 to 0.326 kWh/m3 indicates a near 22-fold increase in energy efficiency. Characterizations involving electron microscopies, electrochemical experiments and density functional theory calculations confirm that hydroxyl radicals (•OH) and adsorbed PDS(PDS*) are the main active species. Molybdenite’s surface with plenty of edge-S, released S vacancy during electrocatalytic oxidation, providing adsorption and activation sites for PDS and H2O. This led to more active sites and facilitating the generation of PDS*, lowering the energy barrier for •OH formation and boosting the oxidation performance of the 3D system. The results underscore the constructed 3D system is a robust and energy-efficient method for practical water treatment.

Revisiting the persulfate activation performance of seaweed derivied biochars: The composition and origin of pollutant degradation activity

A steady increase in seaweed production necessitates effective strategies to manage its post-production waste and its assosicated CO2 emission. Biochar formation stand out as a promising option, offering significant advantage for persulfate-activated water remediation processes. Herein, we investigated and compared the performance of two seaweed-derived biochars, focusing on their physical characteristics, heteroatoms, and chemical composition in activating persulfate (PS). Although, both seaweeds (Capsosiphon fulvescens (CF) and Undaria pinnatifida (SW)) that studied are edible, they exhibit unique catalytic behavior in the degradation of simazine (SMZ). The differences in simazine degradation activity observed in these biochars were primarily attributed to the description of metal active sites rather than the complex composition and specific surface area of the biochars. The identification of these active sites was achieved through various physical characterization tools (XRD, XPS, BET) and by examining the adsorption models and degradation patterns of simazine under different conditions. Our results demonstrate that the biochar derived from CF (100% removal) seaweed having metal active centres is more catalytic than SW (58.4% removal) derived biochar. ROS quantification and electrochemical studies suggest that simazine degradation occurs through different mechanisms in these biochars. Therefore, the CF-derived biochar catalytic system was optimized for simazine oxidation, with studies focusing on its degradation pathway, intermediate toxicity, and catalytic stability. This comprehensive study outlines the significance of selection of seaweed biomass for optimal activity in the persulfate-based oxidative system.

Adsorptive behavior of Rhodamine B dye over hierarchical N-doped carbons from hexamine-based complexes: Equilibrium and kinetics

Pollution from water-soluble dyes is a common issue due to high toxicity and diffiulty in degradation, and its effectively removal is critical for human health and sustainability. In this work, N-doped hierarchical carbons were derived by facile pyrolysis of Co-including hexamine-based complex using glucose as a cross-linker, showing high removal ability using Rhodamine B (RhB) as a model dye. Porous architecture and N-coordination can be easily altered by pyrolysis temperature, where the GNC-900 sample obtained at 900 °C exhibits the best removal ability even outperforming several classical carbons under equal conditions, owing to synergistic effects from large surface areas, high ratio of pyrrolic-N, enhanced interaction between RhB molecules and pore walls, and possible Co-Nx active sites. Adsorptive behaviour is better fitted by pseudo-second-order kinetic model, and the maximum RhB capacity over GNC-900 determined by Langmuir model is highly up to 400.1 mg/g, following mechanisms of pore filling, π-π conjugation, electrostatic, surface complexation and H-bonding. Thermodynamics indicate that RhB removal is exothermic and spontaneous process. Moreover, GNC-900 can be readily regenerated using ethanol and reused at least six times without notable loss in capacity. This novel method facilitates synthesis of N-doped carbons from metal-based complexes, exhibiting high efficiency as adsorbents for water remediation.

Unlocking the potential of environmentally friendly adsorbent derived from industrial wastes: A review.

With increasing urbanization and industrialization, growing amounts of industrial waste, such as red mud (RM), fly ash (FA), blast furnace slag (BFS), steel slag (SS), and sludge, are being produced, exposing substantial threats to the environment and human health. Given that numerous researchers associate with conventional adsorbents, developing and utilizing industrial wastes derived from adsorption technology still has received limited attention. Utilizing this waste contributes to developing alternative materials with superior performance and significantly reduces the volume of solid waste. The excellent physical and chemical characteristics of these wastes are also investigated in this paper. This review attempts to demonstrate a comprehensive overview of the application of industrial waste-based adsorbent in the adsorption process for removing organic pollutants, dyes, metallic ions, non-metallic ions, and radioactive substances. In addition, industrial waste-based adsorbents are among the most promising and applicable techniques for pollutant removal, offering remarkable adsorption efficiency, rich surface chemistries, reasonable cost, simple operation, and low energy consumption. This review summarizes state-of-the-art advancements in engineered adsorbents (including physical and chemical modifications). It provides a holistic view regarding a comprehensive understanding of the mechanism involved in adsorption for water remediation. The challenges and the prospects for future research in applying these adsorbents are also elucidated, contributing to sustainable waste management and environmental sustainability.

SnS2/ZIF-67 nanocomposite: a novel bifunctional, highly efficient, and reusable photocatalyst for enhanced visible-light-assisted biodiesel production and degradation of tinidazole

Herein, a novel bifunctional, highly efficient and reusable visible-light active SnS2/ZIF-67 nanocomposite was fabricated for improved photodegradation of tinidazole (TDZ) and photocatalytic biodiesel production from soyabean oil. An improved photocatalytic performance was ascribed to the enhanced separation of charges and narrow-bandgap energy of the photocatalyst by synergistic- interaction between SnS2 and ZIF-67. Within 60 min of irradiation, more than 96.31± 1.62 % of 15 ppm TDZ could be removed by 0.3 mM H2O2, 0.4 g/L of prepared photocatalyst under mild-conditions. The appraisal of photocatalytic activity of SnS2/ZIF-67 nanocomposite for photocatalytic degradation of TDZ under actual wastewater conditions was studied by introducing various co-existing ions and water matrices. The SnS2/ZIF-67 photocatalyst showed biodiesel yield of 91.25 ± 1.58 % at photocatalyst loading of 3 wt.% and methanol-to-oil ratio of 10:1 within 50 min of light-irradiation. The current research highlighted the potential of metal-sulphides for water remediation and biodiesel production under light-irradiation.

Mercury adsorption study and DFT calculations of sulfur-containing biomass composites prepared by inverse vulcanization

This study introduces an innovative and cost-effective biomass adsorbent, the sulfur/cardanol/potato starch composite (SCP), synthesized through inverse vulcanization for the remediation of mercury-contaminated waters. The SCP was characterized using Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS), Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA) and X-ray Diffraction (XRD) to confirm its composition, morphology, and properties. The adsorption capacity of SCP for Hg(II) was 246.88 mg/g with a removal rate of 98.75 %. Adsorption kinetics followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism, while adsorption isotherms were best described by the Langmuir model. Thermodynamic studies confirmed the adsorption process as spontaneous and endothermic. Density Functional Theory (DFT) calculations further elucidate the interaction mechanisms between mercury and the adsorbent, revealing that the thiyl radicals play a crucial role in the adsorption process. The SCP also exhibited a high selectivity for Hg(II) over other co-existing ions and maintains an adsorption capacity over 223.93 mg/g after five regeneration cycles, thus promising practical applications in environmental mercury management.

Advancing Sustainable Water Quality Monitoring and Remediation in Malaysia: Innovative Analytical Solutions for Detecting and Removing Emerging Contaminants

Advancing Sustainable Water Quality Monitoring and Remediation in Malaysia: Innovative Analytical Solutions for Detecting and Removing Emerging Contaminants

Ligand modulated charge transfers in Z-scheme configured Ni-MOF/g-C3N4 nanocomposites for photocatalytic remediation of dye-polluted water

The development of photocatalysts must be meticulous, especially when they are designed to degrade hazardous dyes that cause mutagenesis and carcinogenesis. In this meticulous approach, Ni-based metal–organic frameworks with different ligands, including terephthalic acid (NTP), 2-aminoterephthalic acid (NATP), and their composite with g-C3N4 (NTP/GCN, and NATP/GCN) have been synthesized using hydrothermal method. Structural analysis by XRD and ATR-IR revealed synergistic properties due to robust chemical interactions between the NATP-MOFs and GCN systems. A flower-like morphology was observed for both NTP and NATP, while their composites showed mixed-particulate structures mimicking the morphology of GCN. Optical analyses indicated visible-light driven properties with modulated recombination resistance in the system. Among the synthesized bare and composite systems, NATP/GCN exhibited the highest photocatalytic degradation efficiency for the cationic rhodamine B dye (~ 93% in 120 min), while it was relatively less efficient for the anionic Congo red dye, (~ 64% in 120 min). The insights gained from the fundamental characterizations including Mott–Schottky, scavenger, and electrochemical impedance analysis revealed that the amino-groups in NATP/GCN composite offered the band edge potentials suitable for the effective generation of energetic radical species with the improved carrier delocalization, recombination resistance, and charge transfer properties in the composite system through Z-scheme formation. Parametric investigations by varying the concentration of catalyst, dye, and pH along with recycle studies, demonstrated the excellent stability of the developed composites for sustainable photocatalytic applications.

Natural and synthetic hydrogels for dye removal

In recent years, dyes have been classified as recalcitrant contaminants in wastewater, exhibiting significant toxicological characteristics for flora, fauna, and humans. Various techniques are currently being studied for the remediation of water contaminated with dyes. Among the most relevant alternative technologies are bioadsorption, biocoagulation, the use of composite materials, advanced oxidation processes, etc. However, these methods have some disadvantages. Similarly, the use of hydrogels specifically designed for the treatment of contaminated water is a viable and effective alternative. This is due to their ability to adsorb large amounts of water, high porosity, and multiple active sites. This research describes dyes, their classification,toxicity, and ecotoxicity. Additionally, it presents some alternative treatments for water remediation, emphasizing the design of hydrogels based on synthetic and natural macromolecules. These hydrogels are proposed as promising materials for the removal of dyes from contaminated water. The aim of this research is to highlight synthetic and natural hydrogels as promising materials for the decontamination of water from dyes.

Harnessing the interfacial charge transfer in Mn-doped γ-Fe2O3@ZnO heterojunction for broad spectrum photocatalytic degradation of organic dyes

Developing affordable, sustainable, and environmentally friendly water remediation strategies is inevitable to achieve water security worldwide. To align with these challenges, this investigation successfully synthesized low-cost Mn-doped iron oxide and its heterojunction with Zinc Oxide (ZnO) as an efficient recovery mechanism for deteriorated water. Comprehensive characterization of Mn-doped γ-Fe2O3@ZnO heterojunction was performed using X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy, Energy dispersive X-ray, and Photoluminescence analysis. The electrical behaviors of all samples were characterized using Electrochemical impedance spectroscopy and Mott-Schottky analysis. This heterojunction showed distinct structural features along with a bandgap energy of 2.61 eV, confirming the formation of a heterojunction. The effectiveness of this heterojunction was assessed using Congo red (CR) and Crystal violet as model pollutants. The photodegradation capability using a small amount of as-synthesized photocatalyst (10 mg) reached 90.8 % for CR and 90.5 % for CV under natural sunlight for a duration of 105 min. The key findings of this report clearly demonstrated the effectiveness of the interfacial charge transfer mechanism of Mn-γ-Fe2O3@ZnO heterojunction towards the degradation of organic water contaminants.

Rapid preparation of N,P co-doped carbon for advanced oxidative degradation of wastewater

Heteroatom-doped porous carbon materials are highly favored as catalysts for activating persulfates in the oxidative degradation of organic pollutants due to their low metal leaching risk and cost-effectiveness. Nonetheless, the complex process of creating heteroatom-doped carbon materials often results in suboptimal doping effects. This study uses N,P-enriched plants (Eichhornia crassipes after being used for nutrient-rich water remediation) as a raw material to prepare N-P co-doped catalysts in a single step. We thoroughly investigated their performance and mechanisms in dye degradation. The findings demonstrated that the adsorbent, with its rich pore structures, surface chemical functional groups, and graphite defect structures, could completely degrade a 100 mg L−1 MB solution within 20 min. Free radical quenching experiments and EPR analysis confirmed the presence of •OH, SO4•—, O2•— and 1O2, verifying their oxidative contributions. Moreover, it was determined that the non-radical pathway (1O2 oxidation) primarily drives the oxidative degradation in this system. Additionally, tests using a small-scale fixed-bed reactor and interference resistance highlighted the practical application potential of the adsorbent developed in this study. This study not only offers a dual solution for tackling nutrient enrichment and organic pollution in water bodies but also introduces a straightforward method for preparing N, P co-doped catalysts, significantly benefiting environmental protection.

Polyoxometalate Derived Materials as Laccase‐Mimic Nanozyme and Reduction Catalyst for p‐Nitrophenol Remediation in Water

Abstractp‐Nitrophenol (PNP), a highly toxic water pollutant, poses significant risks to human health and the environment. For detecting PNP, a colorimetric method utilizing a nanozyme that mimics laccase activity presents a viable approach. In this study, PV14@MIL‐88A, a robust nanozyme with superior laccase‐mimic capabilities, was synthesized by incorporating Na7H2[PV14O42] (PV14) into MIL‐88A, a metal‐organic framework (MOF). This nanozyme demonstrates optimal laccase‐mimicking activity, enabling effective PNP detection via colorimetry and digital image colorimetry using smartphones. Theoretical analyses suggest that the outstanding laccase‐mimic activity of PV14@MIL‐88A is derived from the optimized d‐band center in PV14. Upon calcination with dicyandiamide (DCDA), PV14@MIL‐88A transforms into Fe2O3/VO2@NCNF. In the presence of NaBH4, Fe2O3/VO2@NCNF facilitates the conversion of PNP to p‐aminophenol (PAP), an essential precursor in paracetamol synthesis. The interaction between Fe2O3 and VO2 in Fe2O3/VO2@NCNF enhances adsorption and subsequent reduction of PNP. The saturation magnetization of Fe2O3/VO2@NCNF reaches 25 emu g−1, which supports efficient magnetic separation in the reduction process. This study not only advances an effective method for PNP detection but also facilitates its transformation from a hazardous pollutant into a valuable chemical precursor.