Removal of endrin and dieldrin isomeric pesticides through stereoselective adsorption behavior on the graphene oxide-magnetic nanoparticles

Graphene-based nanomaterials as potential candidates for environmental mitigation of pesticides

Over the years, bioaccumulation of hazardous chemicals in the food chain has become a critical issue, resulting in numerous health risks. Environmental mitigation aims to clean up contaminated sites and eliminate hazardous materials from the air, water, or soil to restore the site to its original and safe condition. Pesticides constitute one of the most dangerous environmental pollutants which are generally used to increase crop production. Addressing the removal or treatment of pesticides has become pivotal in mitigating environmental threats. Diverse remediation methods are employed to protect the environment and public health. Graphene-based materials have emerged as promising candidates with exceptional properties, including excellent adsorption capacity due to their high surface area, strong hydrophilicity, and tunable properties. Owing to these properties, they have been attracting major research attention in the field of design and fabrication of materials for the mitigation of pesticides from the environment such as from contaminated food, water and other samples. Various physical, chemical and biological extraction techniques are adopted to remove pesticides. This review article provides an insight into the potential role of graphene-based materials in the environmental remediation of pesticides. We have focused on the removal of Organophosphates, Organochlorines, Carbamates and Pyrethroids present in water, fruit, vegetable and other samples, highlighting the urgent need for environmental remediation. While graphene-based materials hold potential for pesticide remediation, addressing challenges in scalable production, assessing long-term sustainability, and mitigating potential environmental impacts are critical steps for successful large-scale applications.

Challenges and effectiveness of nanotechnology-based photocatalysis for pesticides-contaminated water: A review

Pesticides have been frequently used in agricultural fields. Due to the expeditious utilization of pesticides, their excessive usage has negative impacts on the natural environment and human health. This review discusses the successful implications of nanotechnology-based photocatalysis for the removal of environmental pesticide contaminants. Notably, various nanomaterials, including TiO₂, ZnO, Fe₂O₃, nanoscale zero-valent iron, nanocomposite-based materials, have been proposed and have played a progressively essential role in wastewater treatment. In addition, a detailed review of the crucial reaction condition factors, including water matrix, pH, light source, temperature, flow rate (retention time), initial concentration of pesticides, a dosage of photocatalyst, and radical scavengers, is also highlighted. Additionally, the degradation pathway of pesticide mineralization is also elucidated. Finally, the challenges of technologies and the future of nanotechnology-based photocatalysis toward the photo-degradation of pesticides are thoroughly discussed. It is expected that those innovative extraordinary photocatalysts will significantly enhance the performance of pesticides degradation in the coming years.

Adsorption of persistent organic pollutants (POPs) from the aqueous environment by nano-adsorbents: A review

The intensification of urbanisation and industrial activities significantly exacerbates the distribution of toxic contaminations into the aqueous environment. Persistent organic pollutants (POPs) have received considerable attention in the past few decades because of their persistence, long-distance migration, potential bioaccumulation, latent toxicity for humans and wildlife. There is no doubt that POPs cause serious effects on the global ecosystem. Therefore, it is necessary to develop a simple, safe and sustainable approach to remove POPs from water bodies. Among other conventional techniques, the adsorption process has proven to be a more effective method for eliminating POPs and to a larger extent meet discharge regulations. Nanomaterials can effectively adsorb POPs from aqueous solutions. For most POPs, a >70% adsorptive removal efficiency was achieved. The major mechanisms for POPS uptake by nano-adsorbents includes electrostatic interaction, hydrophobic (van der Waals, π-π and electron donor-acceptor) interaction and hydrogen bonding. Nano-adsorbent can sustain a >90% POPs adsorptive removal for about 3 cycles and reuseable for up to 10 cycles. Challenges around adsorbent ecotoxicity and safe disposal were also discussed. The present review evaluated recent research outcomes on nanomaterials that are employed to remove POPs in water systems.

Synthesis, Characterization, and Evaluation of the Remediation Activity of Cissus quadrangularis Zinc Oxide Nanoparticle-Activated Carbon Composite on Dieldrin in Aqueous Solution

In this study, zinc oxide-activated carbon nanocomposite was used as the adsorbent for the remediation of dieldrin in aqueous media. Zinc oxide nanoparticles (ZNPs) were synthesized from Cissus quadrangularis (C. quadrangularis) leaf extract, and activated carbon was derived from maize cobs. Nanocomposites were formulated by mixing the ZNPs with the activated carbon in a ratio of 1 : 50. The UV-Vis spectra showed a complete reduction of Zn2+ to Zn0 with plasmon resonance bands in the range of 361–376 nm, which is a characteristic of ZNPs. The SEM images of ZNPs showed hexagonal-shaped particles of 15–20 nm, with face-centered cubic crystals, as demonstrated by XRD analysis. FTIR results showed absorption bands in the ranges 3500–3100 cm−1 (N-H stretch), 3400–2400 cm−1 (O-H stretch), 988–830 cm−1 (C-H bend), 1612 cm−1 (C=C stretch), 400–600 cm−1 (Zn-O stretch), and 1271 cm−1 (C-O bend). Batch adsorption experiments were performed using 20 ml of dieldrin solution at varying pH values (1–14), concentrations (5–100 ppm), temperatures (293–323 K), adsorbent dosages (0.01–0.12 g), and contact times (30–180 minutes) to determine the optimum conditions. The calculated thermodynamic parameters (ΔH°, ΔS°, and ΔG°) indicated that the adsorption was spontaneous and exothermic in nature, implying decreasing randomness of dieldrin molecules at the solid-liquid interface. The isotherm and adsorption kinetics for the composite showed that the absorption process followed Langmuir isotherm and pseudo-second-order kinetics. Adsorption capacities of the nanoparticles, activated carbon, and nanocomposite at a reaction time of 120 minutes and pH of 7 were 3.72 ± 0.068 mg/g, 3.92 ± 0.061 mg/g, and 4.0 ± 0.102 mg/g, respectively, with corresponding percentage removals of 93.12 ± 0.044, 98.04 ± 0.044, and 99.76 ± 0.332. Thus, the nanocomposite exhibited a better sorbing potential for dieldrin in solution than activated carbon. This study recommends testing the remediation potential of the synthesized nanocomposite on other persistent organic pollutants.

Recent insights into SnO2-based engineered nanoparticles for sustainable H2 generation and remediation of pesticides

Due to the ongoing industrial revolution and global health pandemics, solar-driven water splitting and pesticide degradation are highly sought to cope with catastrophes such as depleting fossil reservoirs, global warming, and environmental degradation.

Matrix-dispersed magnetic molecularly-imprinted polyaniline for the effective removal of chlorpyrifos pesticide from contaminated water

We report a new adsorbent nanocomposite material based on matrix-dispersed superparamagnetic iron oxide nanoparticles (SPIONs) in molecularly-imprinted polyaniline for the removal of chlorpyrifos (CPF), a hazardous organophosphate pesticide, from water. The synthesized magnetic molecularly-imprinted polymer (MMIP) was characterized by FTIR spectroscopy, XRD, magnetic susceptibility, DLS, zeta potential measurement, SEM and high-resolution TEM imaging. The average size of the naked SPIONs ranges from 15 to 30 nm according to the high-resolution TEM analysis. Moreover, the adsorption kinetics, thermodynamic parameters (ΔG, ΔH and ΔS), adsorption isotherms and rebinding conditions were investigated in detail. The proposed MMIP has an imprinting factor of 1.64. In addition, it showed a high experimental adsorption capacity of 1.77 mg g⁻¹ and a removal efficiency of nearly 80%. The fabricated MMIP material demonstrated excellent magnetic susceptibility allowing for easy separation using an external magnetic field. The adsorption mechanism of CPF onto the MMIP adsorbent followed the second-order kinetics model and fitted to the Temkin adsorption isotherm. By studying the adsorption thermodynamics, negative ΔG values (−1.955 kJ mol⁻¹ at room temperature) were obtained revealing that the adsorption process is spontaneous. Furthermore, the maximum adsorption capacity was obtained at room temperature (ca. 303 K), neutral pH and using a high CPF concentration.

An efficient magnetic molecularly-imprinted polymer adsorbent for removal of chlorpyrifos organophosphate pesticide from water is reported.

Detection and remediation of pollutants to maintain ecosustainability employing nanotechnology: A review

Environmental deterioration due to anthropogenic activities is a threat to sustainable, clean and green environment. Accumulation of hazardous chemicals pollutes soil, water and air and thus significantly affects all the ecosystems. This article highlight the challenges associated with various conventional techniques such as filtration, absorption, flocculation, coagulation, chromatographic and mass spectroscopic techniques. Environmental nanotechnology has provided an innovative frontier to combat the aforesaid issues of sustainable environment by reducing the non-requisite use of raw materials, electricity, excessive use of agrochemicals and release of industrial effluents into water bodies. Various nanotechnology based approaches including surface enhance scattering, surface plasmon resonance; and distinct types of nanoparticles like silver, silicon oxide and zinc oxide have contributed significantly in detection of environmental pollutants. Biosensing technology has also gained significant attention for detection and remediation of pollutants. Furthermore, nanoparticles of gold, ferric oxide and manganese oxide have been used for the on-site remediation of antibiotics, organic dyes, pesticides, and heavy metals. Recently, green nanomaterials have been given more attention to address toxicity issues of chemically synthesized nanomaterials. Hence, nanotechnology has provided a platform with tremendous applications to have sustainable environment for present as well as future generations. This review article will help to understand the fundamentals for achieving the goals of sustainable development, and healthy environment.

New frontiers and prospects of metal-organic frameworks for removal, determination, and sensing of pesticides

Pesticides have been widely used in agriculture to control, reduce, and kill insects. Humans are also being using pesticides to control insidious animals in daily life. By these practices, a huge volume of pesticides is introduced to the environment. Despite broad-spectrum applicability, pesticides also have hazardous effects on both humans and animals at high and low concentrations. Long-term exposure to pesticides can cause different diseases, like leukemia, lymphoma, and cancers of the brain, breasts, prostate, testis, and ovaries. Reproductive disorders from pesticides include birth defects, stillbirth, spontaneous abortion, sterility, and infertility. Therefore, the application of determination and treatment methods for pre-concentration and removal of these toxic materials from the environment appears a vital concern. To date, different materials and approaches have been employed for these purposes. Among these approaches, multifunctional metal-organic frameworks (MOFs)-assisted adsorption and determination processes have always been in the spotlight. These facts are due to exclusive properties of MOFs in terms of the crystallinity, large surface area, high chemical, and physical stability, and controllable structure as well as unique features of adsorption and determination process in terms of simple, easy, cheap, available method and ability to use in large and industrial scales. In the present work, we illustrate the exceptional features of MOFs as well as the possible mechanism for the adsorption of pesticides by MOFs. The use of these fantastic materials for pre-concentration and removal of pesticides are extensively explored. In addition, the performance of MOFs was compared with other adsorbents. Finally, the new frontiers and prospects of MOFs for the determination, sensing, and removal of pesticides are presented.

Strong Adsorption of Dieldrin by Parent and Processed Montmorillonite Clays

Widespread use of pesticides has resulted in the accumulation of pesticide residues in the environment due to their persistence and stability. To reduce potential exposures, we have developed broad-acting clay-based sorbents that can be included in the diet as enterosorbents to reduce the bioavailability and toxicity of chemicals. In the present study, parent and acid-processed calcium montmorillonite clays (CM and APM, respectively) were used to determine their potential as sorbents of the organochlorine insecticide dieldrin. We used adsorption isotherms, thermodynamics, and dosimetry studies to determine the capacities and affinities of the clays, the enthalpies of the binding reactions, and potential doses of sorbent that could protect against high exposures. Adsorption isotherms for APM fit a Langmuir model with high enthalpy (suggesting chemisorption) and high capacity (Qmax value = 0.45 mol kg-1 ), indicating tight binding of dieldrin. Cultures of Hydra vulgaris were used to determine the ability of sorbents to protect a living organism from dieldrin toxicity. The inclusion of acid-processed clays resulted in the highest reduction of dieldrin toxicity (70%) in the hydra. Further work indicated that both CM and APM can significantly reduce the bioavailability of dieldrin from soil (p ≤ 0.01). These results suggest that APM (and similar clays) can be effective sorbents of dieldrin and may be included in the diet and/or soil to protect against environmental exposures. Environ Toxicol Chem 2020;39:517-525. © 2019 SETAC.

Adsorptive removal and photocatalytic degradation of organic pollutants using metal oxides and their composites: A comprehensive review

Metal oxide nanomaterials and their composites are comprehensively reviewed for water remediation. The controlled morphological and textural features, variable surface chemistry, high surface area, specific crystalline nature, and abundant availability make the nanostructured metal oxides and their composites highly selective materials for efficient removal of organic pollutants based on adsorption and photocatalytic degradation. A wide range of metal oxides like iron oxides, magnesium oxide, titanium oxides, zinc oxides, tungsten oxides, copper oxides, metal oxides composites, and graphene-metal oxides composites having variable structural, crystalline and morphological features are reviewed emphasizing the recent development, challenges, and opportunities for adsorptive removal and photocatalytic degradation of organic pollutants viz. dyes, pesticides, phenolic compounds, and so on. It also covers the deep discussion on the photocatalytic mechanism of metal oxides and their composites along with the properties relevant to photocatalysis. High photodegradation efficiency, economically-viable approaches for the preparation of photocatalytic materials, and controlled band-gap engineering make metal oxides highly efficient photocatalysts for degradation of organic pollutants. The review would be an excellent resource for researchers who are currently focusing on metal oxides-based materials for water remediation as well as for those who are interested in adsorptive and photocatalytic applications of metal oxides and their composites.

Removal and extraction efficiency of Quaternary ammonium herbicides paraquat (PQ) from aqueous solution by ketoenol-pyrazole receptor functionalized silica hybrid adsorbent (SiNPz)

Pesticides and herbicides have been used extensively in agricultural practices to control pests and increase crop yields. Paraquat (PQT²⁺, 1,1-dimethyl-4,4-dipyridinium chloride) is one of the herbicide that belois classified as bipyridines and is used over the world. The objective of this study is to use ketoenol–pyrazole receptor functionalized silica hybrid as adsorbent for removal PQT²⁺ from aqueous solution. The adsorbent was synthesized, and characterized using scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), Thermal analysis and other techniques. Different experimental parameters such as the effect of the amount of adsorbent, solution pH and temperatures and contact times were studied. Pseudo-order kinetics models were studied, and our data followed a pseudo second order. Experimental data were analyzed for both Langmuir and Freundlich models and the data fitted well with the Langmuir isotherm model. To understand the mechanism of adsorption, thermodynamic parameters like standard enthalpy, standard Gibbs free energy, and standard entropy were studied. The study indicated that the process is spontaneous, exothermic in nature and follow physisorption mechanisms. The novelty of this study showed surface of pyrazol-enol-imine-substituted silica (SiNPz) has the ability to highlight the surface designed for efficient removal of PQT²⁺, from aqueous solutions more than other studies. The study also showed that ketoenol–pyrazole receptor can be regenerated in five cycles using HNO₃ without affecting its adsorption capacity.

Efficient removal of ethidium bromide from aqueous solution by using DNA-loaded Fe3O4 nanoparticles

Ethidium bromide (EtBr) is widely used as DNA-staining dyes for the detection of nucleic acids in laboratories and known to be powerful mutagens and carcinogens. In the present paper, the removal of EtBr from aqueous solutions in a batch system using DNA-loaded Fe₃O₄ nanoparticles as a simple and efficient method was investigated. DNA was covalently loaded on the surface of Fe₃O₄ magnetic nanoparticles, which was confirmed by FT-IR analysis and zeta potential measurements. The morphology and crystal structure were characterized by SEM, TEM, and XRD. The influence factors on the removal efficiency such as initial EtBr concentration, contact time, adsorbent dose, pH, and temperature were also studied. The removal process of EtBr can be completed quickly within 1 min. The removal efficiency was more than 99% while the EtBr concentration was routinely used (0.5 mg L^-1) in biology laboratories and the dosages of nanoparticles were 1 g L^-1. For the different EtBr concentrations from 0.5 to 10 mg L^-1 in aqueous solution, the goal of optimized removal was achieved by adjusting the dosage of DNA-loaded Fe₃O₄ nanoparticles. The optimum pH was around 7 and the operational temperature from 4 to 35 °C was appropriate. Kinetic studies confirmed that the adsorption followed second-order reaction kinetics. Thermodynamic data revealed that the process was spontaneous and exothermic. The adsorption of EtBr on DNA-loaded Fe₃O₄ nanoparticles fitted well with the Freundlich isotherm model. These results indicated that DNA-loaded Fe₃O₄ nanoparticles are a promising adsorbent for highly efficient removal of EtBr from aqueous solution in practice.

Advances of magnetic nanoparticles in environmental application: environmental remediation and (bio)sensors as case studies

Nanotechnology is an emerging technique drawing increasing attentions in biomedical, electronic, environmental, and industrial application. Nanoparticles (NPs) possess unique optical, electrical, catalytic, and thermal properties, among which magnetic NPs (MNPs) are one of the most important groups with excellent superparamagnetism property, large surface area, and biocompatibility. In this review, methods for synthesizing and functionalizing MNPs are summarized and linked to their applications in environmental science as either adsorbents or catalysts for removing contaminants from environmental matrices, illustrating stronger reactivity, higher removal capacity, and fast kinetics. Additionally, we also comprehensively discuss the application of MNPs as (bio)sensors to selectively and sensitively detect the presence of environmental contaminants or pathogenic bacteria. This work summarizes the recent progresses of using MNPs as powerful tools in environmental science and engineering, raising their state-of-art application from environmental perspectives and benefiting researchers interested in NPs and environmental studies.