Removal of endosulfan by sal wood charcoal

Fate of endosulfan in ginseng farm and effect of granular biochar treatment on endosulfan accumulation in ginseng

Endosulfan was widely used as an insecticide in the agricultural sector before its environmental persistence was fully understood. Although its fate and transport in the environment have been studied, the effects of historic endosulfan residues in soil and its bioaccumulation in crops are not well understood. This knowledge gap was addressed by investigating the dissipation and bioaccumulation of endosulfan in ginseng as a perennial crop in fresh and aged endosulfan-contaminated fields. In addition, the effect of granular biochar (GBC) treatment on the bioaccumulation factor (BAF) of endosulfan residue in ginseng was assessed. The 50% dissipation time (DT₅₀) of the total endosulfan was over 770 days in both the fresh and aged soils under mulching conditions. This was at least twofold greater than the reported (6- > 200 days) in arable soil. Among the endosulfan congeners, the main contributor to the soil residue was endosulfan sulfate, as observed from 150 days after treatment. The BAF for the 2-year-old ginseng was similar in the fresh (1.682-2.055) and aged (1.372-2.570) soils, whereas the BAF for the 3-year-old ginseng in the aged soil (1.087-1.137) was lower than that in the fresh soil (1.771-2.387). The treatment with 0.3 wt% GBC extended the DT₅₀ of endosulfan in soil; however, this could successfully suppress endosulfan uptake, and reduced the BAFs by 66.5-67.7% in the freshly contaminated soil and 32.3-41.4% in the aged soil. Thus, this adsorbent treatment could be an effective, financially viable, and sustainable option to protect human health by reducing plant uptake of endosulfan from contaminated soils.

Sorption/Desorption and Kinetics of Atrazine, Chlorfenvinphos, Endosulfan Sulfate and Trifluralin on Agro-Industrial and Composted Organic Wastes

The use of pesticides presents a risk to terrestrial and aquatic ecosystems. For this reason, the development of strategies to prevent and restore pollution is of the greatest interest, including the adsorption to organic matter. The aim of the present study was to investigate the sorption/desorption and kinetics of atrazine, chlorfenvinphos, endosulfan sulfate, and trifluralin onto several raw organic wastes by batch experiments. Three kinetic models were used to fit the obtained sorption kinetics data and two to fit the obtained adsorption isotherm data; both the Freundlich and pseudo-second-order kinetic models described the sorption isotherms well. The desorption study revealed hysteresis in all cases, showing strong, and not completely reversible, adsorption in most cases, with the exception of atrazine-sawdust and chlorfenvinphos-sawdust and chicken manure combinations, for which responses were weak and irreversible. The best kinetic, adsorption and desorption constants were achieved for the hydrophobic pesticides. With respect to sorption-desorption rates, orujillo was found to be the best adsorbent for atrazine, while composted urban solid waste was more suitable for trifluralin and endosulfan sulfate. Sorption constants and simple correlations indicated that, not only the organic matter content, but also the nature of the organic matter itself, and the pesticide and adsorbent properties, determine pesticide sorption-desorption. The use of wastes as efficient and cheap adsorbents for reducing the risk of pesticide pollution is proposed.

Iron turning waste: Low cost and sustainable permeable reactive barrier media for remediating dieldrin, endrin, DDT and lindane in groundwater

The feasibility and effectiveness of iron turning waste as low cost and sustainable permeable reactive barrier (PRB) media for remediating dieldrin, endrin, dichlorodiphenyltrichloroethane (DDT), and lindane individually (batch system) and combined (continuous flow column) in water were investigated. After 10 min of reaction in a batch system, removal of endrin, dieldrin, and DDT was higher (86-91 %) than lindane (41 %) using 1 g of iron turning waste in 200 mL of pesticide solution (20 μg/L for each pesticide). Among the studied pesticides, only lindane removal decreased substantially in the presence of nitrate (37 %) and magnesium (18 %). Acidic water environment (pH = 4) favored the pesticide removal than neutral and basic environments. For the column experiments, sand alone as PRB media was ineffective for remediating the pesticides in water. When only iron turning was used, the removal efficiencies of lindane, endrin, and dieldrin were 83-88 % and remained stable during 60 min of the experiments. DDT removal was less than other pesticides (58 %). Sandwiching the iron turning waste media between two sand layers improved DDT removal (79 %) as well as limited the iron content below a permissible level in product water. In a long-term PRB column performance evaluation, iron turning waste (150 g) removed all pesticides in water (initial concentration of each pesticide = 2 μg/L) effectively (≥94 %) at a hydraulic retention time of 1.6 h. Iron turning waste, which was mainly in the form of zerovalent iron (Fe⁰), was oxidized to ferrous (Fe²⁺) and ferric (Fe³⁺) iron during its reaction with pesticides, and electrons donated by Fe⁰ and Fe²⁺ were responsible for complete dechlorination of all the pesticides. Therefore, it can be used as inexpensive and sustainable PRB media for groundwater remediation especially in developing countries where groundwater contamination with pesticides is more prevalent.

Rapid biodegradation and biofilm-mediated bioremoval of organophosphorus pesticides using an indigenous Kosakonia oryzae strain -VITPSCQ3 in a Vertical-flow Packed Bed Biofilm Bioreactor

The widespread use of pesticides has been one of the major anthropogenic sources of environmental pollution. Organophosphorus (OP) pesticides are predominantly used in agriculture due to their broad-spectrum insecticidal activity and chemical stability. The study was focused on the biodegradation of OP pesticides, Profenofos (PF) and Quinalphos (QP) in culture media using bacterium isolated from wetland paddy rhizosphere. The strain VITPSCQ3 showed higher pesticide tolerance, efficient biofilm formation and was capable of synthesizing organophosphate degrading enzymes. Based on the 16S rRNA gene sequencing the isolate exhibited maximum sequence similarity with Kosakinia oryzae (GenBank accession number: KR149275). Biodegradation assay with various concentrations of PF and QP (200, 400, 600 and 800 mg L^-1) showed maximum degradation up to 82% and 92% within 48 h. The kinetic studies revealed the biodegradation rates (k) to be 0.0844 min^-1 and 0.107 min^-1 with half-lives (h) of 18 h and 14.8 h for PF and QP. The degradation products were identified by GCMS and possible degradation pathways were proposed using Insilico techniques. To the best of our knowledge, this is the first report on the biodegradation of PF and QP using Kosakonia oryzae. Bioremoval of PF and QP from aqueous solution was performed using the biofilm of VITPSCQ3 developed on selected substrates in a circulating Vertical-flow packed-bed biofilm (VFPBB) bioreactor. Charcoal, gravel and mushroom (Agaricus bisporus) were used as biofilm carriers. Mushroom showed strong biofilm formation with optimum biodegradation capacity of up to 96% for PF and 92% for QP within 120 min reaction time.

Iron turning waste media for treating Endosulfan and Heptachlor contaminated water

This study explored the application of iron turning waste for the degradation of heptachlor and endosulfan. In batch experiments, 2.5 g of iron turning waste efficiently removed 96% of heptachlor and 85% of endosulfan in 200 mL of water (20 μg/L for each pesticide) in ten minutes. By increasing the iron turning dose from 1 g to 2.5 g, pseudo second order removal rates of heptachlor and endosulfan increased 1.5-fold and 1.37-fold, respectively. Among the minerals in groundwater, calcium and potassium lowered heptachlor removal (8-10%), whereas their effect on endosulfan removal was minimal. Endosulfan removal increased 16%, when water pH was raised from 4 to 10. The effect of water pH on heptachlor removal was minimal. The removal of heptachlor and endosulfan dropped to 55% and 46%, respectively, when the initial concentration was 1 μg/L. In a continuous flow system, iron turning worked better in combination with sand media. Water flow rate (5-15 mL/min) had a limited effect on the removal of both pesticides (initial concentration of 2 μg/L) which increased with increasing iron turning dose (100-150 g) for endosulfan. Heptachlor removal remained stable (100%) regardless of the iron turning amount (100-150 g) used in a filtration column. Iron turning based filter completely removed heptachlor throughout the filtration period (600 h), whereas endosulfan removal dropped from 100% to 88-90% after 300 h. Endosulfan and heptachlor were degraded into nonanal and heptanal, respectively. Iron turning waste was characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) before and after its reactions with both pesticides. XRD and XPS analyses revealed that virgin iron turning waste consisted of zerovalent iron (Fe⁰) and iron oxides, and Fe⁰ was transformed to magnetite (Fe₃O₄) after reacting with both pesticides. Based on detected degradation by-products, the removal mechanism and degradation pathways for both pesticides were elucidated.

Solvent effect on endosulfan adsorption onto polymeric arginine-methacrylate cryogels

Endosulfan is a persistent insecticide that is still used in some countries even though it is life-threatening and banned in the agricultural struggle. The solubility of pesticides in water is negligible. It is known that pesticides with better solubility in organic solvents have different solubility when the dielectric constants of these solvents are taken into account. The polymeric structure of arginine was modified with methacrylate to be a functional monomer, and it was immobilized on a solid support, poly(HEMA), and finally, poly(2-hydroxyethyl methacrylate-arginine methacrylate) was obtained and used as an effective adsorbent. The effect of organic solvents on endosulfan adsorption was investigated for the first time in the literature. Endosulfan was removed from alcohol media by using this polymeric structure synthesized by exploiting alcoho-phobic interaction in this work. Nuclear magnetic resonance (NMR), elemental analysis, and Fourier transform infrared spectroscopy (FTIR) methods were used for the structural characterization and therefore to prove successful synthesis of cryogels. Morphological characteristics were also investigated by scanning electron microscopy (SEM), an N₂ adsorption method, and swelling test. Adsorption experiments were carried out against varying interaction time and concentration parameters in the batch system. Since the alcohol used as a solvent has a pH value close to the ionic strength of drinking water, no change was made in the pH of the solution. Endosulfan molecules dissolved in solvents such as toluene, dichloromethane, acetone, and chloroform were removed using poly(HEMA-ArMA) cryogels to determine the solvent effect on the adsorption of endosulfan. As expected, the removal of endosulfan from the solvent toluene provided the best result. Although the adsorption in toluene is almost 9.5 times higher than that in ethanol, the use of toluene in the adsorption process due to its chemical structure is not feasible. Thus, experiments were carried out in ethanol.

Fate of mixed pesticides in an integrated recirculating constructed wetland (IRCW)

In this study, three model integrated recirculating constructed wetlands (IRCWs) planted with and without Cyperus alternifolius were used to investigate their ability to remove four pesticides (chlorpyrifos, endosulfan, fenvalerate, diuron). Iron (Fe)-impregnated biochar produced by Cyperus alternifolius was added as a primary substrate. Results showed that all four pesticides were efficiently removed in the three IRCWs. The highest pesticide removals were achieved when Fe-impregnated biochar was added to the IRCW (99%), followed by the planted (64-99%) and plant-free IRCW (45-99%). The removal of pesticides in IRCWs followed first-order kinetics, with half-lives of 1.5-11.6h. A mass balance study revealed that sorption (32.2-98.6%) and microbial degradation (1.3-52.8%) were the main removal processes in all IRCWs. This study suggests that the IRCW is a promising system to treat pesticide-contaminated water, and plant and Fe-impregnated biochar can enhance pesticide removal.

Mobile soak pits improve spray team mobility, productivity and safety of PMI malaria control programs

In the President's Malaria Initiative (PMI)-funded Africa Indoor Residual Spraying Project (AIRS), end-of-day clean-up operations require the safe disposal of wash water resulting from washing the exterior of spray tanks and spray operators' personal protective equipment. Indoor residual spraying (IRS) programs typically use soak pits - large, in-ground filters - to adsorb, filter and then safely degrade the traces of insecticide found in the wash water. Usually these soak pits are permanent installations serving 30 or more operators, located in a central area that is accessible to multiple spray teams at the end of their workday. However, in remote areas, it is often impractical for teams to return to a central soak pit location for cleanup. To increase operational efficiency and improve environmental compliance, the PMI AIRS Project developed and tested mobile soak pits (MSP) in the laboratory and in field applications in Madagascar, Mali, Senegal, and Ethiopia where the distance between villages can be substantial and the road conditions poor. Laboratory testing confirmed the ability of the easily-assembled MSP to reduce effluent concentrations of two insecticides (Actellic 300-CS and Ficam VC) used by the PMI AIRS Project, and to generate the minimal practicable environmental "footprint" in these remote areas. Field testing in the Mali 2014 IRS campaign demonstrated ease of installation and use, resulted in improved and more consistent standards of clean-up, decreased transportation requirements, improved spray team working conditions, and reduced potential for operator exposure to insecticide.

Reductive dehalogenation of endosulfan by cast iron: Kinetics, pathways and modeling

Cast iron has been a material of choice for in-situ remediation of groundwater. In this study interaction of endosulfan with High Carbon Iron Filings (HCIF) was studied in batch reactors. Decline in total concentration (Ct) could be related to aqueous concentration (Ca) by equation dCt/dt = k1.M.Ca(n), where reaction rate constant (k1) and order (n) were found to be 1.246 × 10(-4) L g(-1) iron h(-1) and 1.47, respectively. Partitioning of endosulfan to HCIF could be explained by Freundlich isotherm. The process of simultaneous reductive dehalogenation and adsorption/desorption was successfully modelled. The reductive dehalogenation of endosulfan resulted in by-products identified as [(3a, alpha,7beta,7a alpha,8s)-4,5,6,7,8 Pentachloro 3a,4,7,7a-tetrahydro] (C9H3Cl5O3) and Benzofuran,4,5,7-trichloro-2,3-dihydro-2-methyl (C9H7Cl3O).

The removal of organophosphorus pesticides from water using a new amino-substituted calixarene-based magnetic sporopollenin

This study describes the synthesis, characterization and application of a new amino-substituted p-tert-butylcalix[4]arene-based magnetic sporopollenin, Calix-EPPTMS-MS (4), for the removal of two toxic organophosphorus pesticides from water.

Characterization of sorption processes for the development of low-cost pesticide decontamination techniques

The adsorption/desorption behavior of four pesticides (atrazine, alachlor, endosulfan sulfate and trifluralin) in aqueous solutions onto four adsorbents (sunflower seed shells, rice husk, composted sewage sludge and soil) was investigated. Pesticide determination was carried out using stir bar sorptive extraction and gas chromatography coupled with mass spectroscopy. Maximum removal efficiency (73.9%) was reached using 1 g of rice husk and 50 mL of pesticide solution (200 μg L(-1)). The pseudo adsorption equilibrium was reached with 0.6 g organic residue, which was used in subsequent experiments. The pseudo-first-order, pseudo-second-order kinetics and the intra-particle diffusion models were used to describe the kinetic data and rate constants were evaluated. The first model was more suitable for the sorption of atrazine and alachlor while the pseudo-second-order best described endosulfan sulfate and trifluralin adsorption, which showed the fastest sorption rates. 4h was considered as the equilibrium time for determining adsorption isotherms. Experimental data were modeled by Langmuir and Freundlich models. In most of the studied cases both models can describe the adsorption process, although the Freundlich model was applicable in all cases. The sorption capacity increased with the hydrophobic character of the pesticides and decreased with their water solubility. Rice husk was revealed as the best adsorbent for three of the four studied pesticides (atrazine, alachlor and endosulfan sulfate), while better results were obtained with composted sewage sludge and sunflower seed shell for the removal of trifluralin. Although desorption percentages were not high (with the exception of alachlor, which reached a desorption rate of 57%), the Kfd values were lower than the Kf values for adsorption and all H values were below 100, indicating that the adsorption was weak.

Enhancing soil sorption capacity of an agricultural soil by addition of three different organic wastes

This study evaluated the ability of three unmodified organic residues (composted sewage sludge, RO1; chicken manure, RO2; and a residue from olive oil production called 'orujillo', RO3) and a soil to sorb six pesticides (atrazine, lindane, alachlor, chlorpyrifos, chlorfenvinphos and endosulfan sulfate) and thereby explored the potential environmental value of these organic residues for mitigating pesticide pollution in agricultural production and removing contaminants from wastewater. Pesticide determination was carried out using gas chromatography coupled with mass spectrometry. Adsorption data were analyzed by the Langmuir and Freundlich adsorption approaches. Experimental results showed that the Freundlich isotherm model best described the adsorption process and that Kf values increased with an increase in organic matter (OM) content of the amended soil. The order of adsorption of pesticides on soils was: chlorpyrifos≥endosulfan sulfate>chlorfenvinphos≥lindane>alachlor≥atrazine. The sorption was greater for the most hydrophobic compounds and lower for the most polar ones, as corroborated by a negative correlation between Kf values and solubility. Sorption increased with an increase in organic matter. Sorption capacity was positively correlated with the organic carbon (OC) content. The organic amendment showing the maximum sorption capacity was RO3 in all cases, except for chlorfenvinphos, in which it was RO2. The order of adsorption capacity of the amendments depended on the pesticide and the organic dosage. In the case of the 10% amendment the order was RO3>RO2>RO1>soil, except for chlorfenvinphos, in which it was RO2>RO3>RO1>soil, and atrazine, where RO2 and RO3 amendments had the same effect on the soil sorption capacity (RO2≥RO3>RO1>soil).

Graphene: a reusable substrate for unprecedented adsorption of pesticides

Unprecedented adsorption of chlorpyrifos (CP), endosulfan (ES), and malathion (ML) onto graphene oxide (GO) and reduced graphene oxide (RGO) from water is reported. The observed adsorption capacities of CP, ES, and ML are as high as ~1200, 1100, and 800 mg g(-1) , respectively. Adsorption is found to be insensitive to pH or background ions. The adsorbent is reusable and can be applied in the field with suitable modifications. A first-principles pseudopotential-based density functional analysis of graphene-water-pesticide interactions showed that the adsorption is mediated through water, while direct interactions between graphene and the pesticides is rather weak or unlikely.

An investigation on the sorption behaviour of montmorillonite for selected organochlorine pesticides from water

The sorption behaviour of montmorillonite towards organochlorine pesticides (OCPs) from aqueous solutions is reported. After preliminary investigation of the sorption capability of clay for selected OCPs, aldrin was used as a model compound for further experiments. The batch sorption experiments were carried out as functions of contact time, pH of the solution, initial aldrin concentration and dosage of the montmorillonite. After traditional liquid-liquid extraction, the determination of OCPs was carried out by gas chromatography coupled with a micro-electron capture detector (GC-microECD). The results indicated that sorption of aldrin followed the second-order kinetic model and that the equilibrium time depended on the initial aldrin concentration. The film diffusion was found to be a main sorption rate control mechanism. The removal was explained according to the electrostatic bonding mechanism. The Freundlich isotherm model better represented the sorption data than the Langmuir model. The montmorillonite was also used efficiently for the removal of OCPs from fortified tap and surface (lake) water samples.

An efficient calix[4]arene based silica sorbent for the removal of endosulfan from water

The present work explores sorption behavior of calix[4]arene based silica resin to remove α and β endosulfan isomers from aqueous solution. The efficiency of resin was checked through both batch and column sorption methods. In both methods, the sorption parameters, i.e. pH, equilibrium time, shaking speed and sorbent dosage were optimized as 2, 60 min, 125 rpm and 50 mg, respectively. Freundlich and Langmuir sorption isotherm models were applied to validate the sorption process. The data obtained in both models reveal that the sorption is favorable. Column sorption data were analyzed through Thomas model to calculate kinetic coefficient k(TH) and maximum sorption capacity q(o) of the resin, which were found to be 6.18 and 5.83 cm(3) mg(-1) min(-1) as well as 1.11 and 1.08 mg g(-1) for α and β endosulfan, respectively. Kinetics of sorption shows that it follows pseudo second order rate equation. The optimized method has also been applied to real water samples and the results show that calix[4]arene based silica resin is an effective sorbent to remove endosulfan from waste waters.

Removal of pesticides from water and wastewater by different adsorbents: a review

In this review article, the use of various low-cost adsorbents for the removal of pesticides from water and wastewater has been reviewed. Pesticides may appear as pollutants in water sources, having undesirable impacts to human health because of their toxicity, carcinogenicity, and mutagenicity or causing aesthetic problems such as taste and odors. These pesticides pollute the water stream and it can be removed very effectively using different low-cost adsorbents. It is evident from a literature survey of about 191 recently published papers that low-cost adsorbents have demonstrated outstanding removal capabilities for pesticides.

Sawdust pellets from coniferous species as adsorbents for NO2 removal

Carbonaceous adsorbents based on sawdust pellets from coniferous tree species were obtained by carbonisation at different temperatures and different periods of time. The effect of NO(2) adsorption in dry and wet condition on the sorption ability of the chars obtained was tested. The results have shown that NO(2) sorption properties of chars depend on the conditions of pyrolysis and the conditions of adsorption. The best NO(2) sorption capacity of 18.3 and 43.1mg/g in dry and wet conditions, respectively, was noted for the char sample pyrolysed at 800 degrees C for 60 min. The FTIR spectra of the exhausted samples reveal a great increase in the intensity of the band at approximately 1380 cm(-1) assigned to the vibrations of -NO(2), -ONO(2) or NO(3)(-), while in the DTG curves a new peak appears in the range 200-400 degrees C assigned to the release of nitrogen compounds of low stability in high temperatures.

Adsorption isotherm and kinetic modeling of 2,4-D pesticide on activated carbon derived from date stones

In this work, the adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) on activated carbon derived from date stones (DSAC) was studied with respect to pH and initial 2,4-D concentration. The experimental data were analyzed by the Freundlich isotherm, the Langmuir isotherm, and the Temkin isotherm. Equilibrium data fitted well with the Langmuir model with maximum adsorption capacity of 238.10 mg/g. Pseudo-first and pseudo-second-order kinetics models were tested with the experimental data, and pseudo-first-order kinetics was the best for the adsorption of 2,4-D by DSAC with coefficients of correlation R(2)>or=0.986 for all initial 2,4-D concentrations studied. The results indicated that the DSAC is very effective for the adsorption of 2,4-D from aqueous solutions.