Removal Of Methyl Parathion Research Articles

Electrochemical degradation of the insecticide methyl parathion using a boron-doped diamond film anode

Methyl parathion is one of the most toxic of the organophosphate insecticides. While this agent continues to be used, natural waters in agricultural areas are likely to contain significant amounts of the biocide, representing a threat to beneficial insects, freshwater organisms, birds and mammals. The electrochemical oxidation of methyl parathion in acidic medium has been studied using a boron-doped diamond (BDD)/Ti anode under galvanostatic current control. Chronoamperometry showed that significant oxidation of reference standard methyl parathion commenced at 1.8V vs Ag/AgCl, while spectrophotometric studies revealed that the absorbance of a commercial formulation of the insecticide decayed according to time in electrolysis. Electrochemical degradation experiments were performed in a laboratory-constructed polypropylene cell in which solutions containing methyl parathion (equivalent to 60mgL−1) were subjected to electrolytic treatment at different current densities (5, 10, 25, 50 and 100mAcm−2). High performance liquid chromatographic analysis demonstrated that 81.2% of the insecticide was removed in 180min at an applied current density of 100mAcm−2, and a compound, identified from its UV spectrum as 4-nitrophenol, was formed either as an intermediate or as a byproduct. Under these conditions, mineralization efficiency (determined by total organic carbon analysis) was 67.6%, and the toxicity of the original electrolyte against the bioluminescent bacterium Vibrio fischeri was reduced considerably by the electrochemical treatment. It is concluded that electrooxidation using BBD/Ti electrodes represents an appropriate method for the removal of methyl parathion from contaminated waters.

Optimization of aqueous methylparathion biodegradation by Fusarium sp in batch scale process using response surface methodology

Biotreatment of methylparathion (O,O-dimethyl-O-4-nitrophenyl phosphorothioate) was studied in aqueous mineral salts medium containing fungal culture to demonstrate the potential of the pure culture (monoculture) of Fusarium sp in degrading high concentration of methylparathion. A statistical Box–Behnken design of experiments was performed to evaluate the effects of individual operating variables and their interactions on the methylparathion removal with initial concentration of 1,000 mg/L as fixed input parameter. A full factorial Box–Behnken design of experiments was used to construct response surfaces with the removal, the extent of methylparathion biodegradation, removal of chemical oxygen demand and total organic carbon, and the specific growth rate as responses. The temperature (X 1), pH (X 2), reaction time (X 3) and agitation (X 4) were used as design variables. The result was shown that experimental data fitted with the polynomial model. Analysis of variance showed a high coefficient of determination value of 0.99. The maximum biodegradation of methylparathion in terms of the methylparathion removal (Y 1), chemical oxygen demand removal (Y 2) and total organic carbon removal (Y 3) were found to be 92, 79.2 and 57.2 % respectively. The maximum growth in terms of dry biomass (Y 4) was 150 mg/L. The maximum biodegradation corresponds to the combination of following factors of middle level of temperature (X 1 = 30 °C), pH (X 2 = 6.5), agitation (X 4 = 120 rpm) and the highest level of reaction time (X 3 = 144 h). The removal efficiency of methylparathion biodegradation was achieved 92 %. It was observed that optimum biotreatment of methylparathion can be successfully predicted by response surface methodology.

Adsorption of methyl parathion on PAC from natural waters: the effect of NOM on adsorption capacity and kinetics

Source water pollution by agricultural chemicals poses great threat to drinking water safety and the removal of such contaminants is a challenge to the water treatment industry. In this work, the adsorption behaviors of methyl parathion (MP) from different natural waters onto different kinds of powdered activated carbons (PAC) were investigated systematically. On the basis of the characterization of the PACs and natural organic matter (NOM), the suitability of PAC with NOM for effective removal of MP was proposed, and the effect of competitive adsorption on MP removal under two PAC dosing patterns was evaluated. The results indicated that NOM adsorption was dependent on the molecular weight (MW) distribution of organic compounds and the pore size distribution of PAC. The mesopore surface area with pore size > 3 nm was dominant for the adsorption of the NOM fraction in the range of 500 Da < MW < 3000 Da. Competition for adsorption sites by smaller MW NOM had significant effect on the adsorption of target organic compound in the simultaneous adsorption pattern. Whereas in the NOM-preloaded adsorption pattern, pore blockage by relatively larger MW NOM resulted in markedly reduction in both adsorption capacity and adsorption kinetics, the diffusion rate of MP on PAC could be affected by the PAC dosage, pore size distribution and the MW distribution of NOM.

Degradation of methyl parathion using hydrodynamic cavitation: Effect of operating parameters and intensification using additives

Methyl parathion (C8H10NO5PS), which is an organophosphorus pesticide that has been widely used as an agricultural insecticide in India, can result in significant water pollution due to its biorefractory nature and longer stability. In the present work, degradation of methyl parathion has been investigated using hydrodynamic cavitation reactors with possible intensification studies using different approaches. Effect of different parameters like operating pressures (1–8bar), operating temperatures (sets of intense cooling, moderate cooling and uncontrolled operation) and initial pH (2.2–8.2) has been investigated initially. Under the optimized set of operating parameters, the effect of process intensifying parameters like hydrogen peroxide (25–200mg/l), carbon tetrachloride (1–6g/l) and Fenton’s reagent (H2O2:FeSO4 ranging from 1:1 to 1:6) on the extent of degradation has been investigated. Effect of radical scavengers like sodium bicarbonate and tert-butanol on the extent of degradation was also investigated with an objective of establishing the controlling mechanism. More than 90% degradation of methyl parathion was achieved using combination of hydrodynamic cavitation with H2O2 and Fenton’s reagent. TOC analysis at optimum conditions was also performed to quantify the extent of mineralization and it has been observed that a maximum of 76% TOC reduction is obtained. The study has also focused on the determination of intermediate products formed during the degradation. It has been established that hydrodynamic cavitation in the presence of additives can be effectively used for complete removal of methyl parathion.

Genetic surface-display of methyl parathion hydrolase on Yarrowia lipolytica for removal of methyl parathion in water

In this study, the mph gene encoding methyl parathion hydrolase from Pseudomonas sp. WBC-3 was expressed in Yarrowia lipolytica and the expressed methyl parathion hydrolase was displayed on cell surface of Y. lipolytica. The activity of methyl parathion hydrolase displayed on the yeast cells of the transformant Z51 was 59.5 U mg⁻¹ of cell dry cells (450.6 U per mL of the culture) in the presence of 5.0 mM of Co²⁺. The displayed methyl parathion hydrolase had the optimal pH of 9.5 and the optimal temperature of 40 °C, respectively and was stable in the pH range of 4.5-11 and up to 40 °C. The displayed methyl parathion hydrolase was also stimulated by Co²⁺, Cu²⁺, Ni²⁺ and Mn²⁺, and was not affected by Fe²⁺, Fe³⁺, Na⁺, K⁺, Ca²⁺ and Zn²⁺, but was inhibited by other cations tested. Under the optimal conditions (OD(600 nm) = 2.6, the substrate concentration = 100 mg L⁻¹ and 40 °C), 90.8 % of methyl parathion was hydrolyzed within 30 min. Under the similar conditions, 98.7, 97.0, 96.5 and 94.4 % of methyl parathion in tap water (pH 9.5), tap water (pH 6.8), seawater (pH 9.5) and natural seawater (pH 8.2) were hydrolyzed, respectively, suggesting that the methyl parathion hydrolase displayed on the yeast cells can effectively remove methyl parathion in water.

Copper chitosan nanocomposite: synthesis, characterization, and application in removal of organophosphorous pesticide from agricultural runoff

Removal of malathion from agricultural runoff was studied using novel copper-coated chitosan nanocomposite (CuCH)-a biopolymeric waste obtained from marine industry. Synthesis and characterization of the adsorbent using different spectral techniques like Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer, Emmett, and Teller surface analyzer have been carried out. Equilibrium studies have been carried out to optimize the dose rate, pH, and the reaction time. Parathion and methyl parathion removal were also evaluated by CuCH in the batch mode. Using gas chromatography-mass spectrometry (GC-MS) and FTIR studies suitable mechanism for adsorption has been suggested. The particle size of the adsorbent ranged from 700 to 750 nm. The surface area was found to be 20 m(2) g(-1) with a pore volume of 0.11 cc g(-1). The maximum adsorption capacity of malathion by CuCH was found to be 322.6 ± 3.5 mg g(-1) at an optimum pH of 2.0. Presence of copper ions enhanced the adsorption capacity of the adsorbent. The reaction was found to follow pseudo second-order kinetics with a rate constant of 0.53 g mg(-1) min(-1). Evidence from FTIR indicated that copper ions form a dithionate complex with malathion during the adsorption stage. The adsorbent was found to remove malathion completely from spiked concentration of 2 mg l(-1) in the agricultural run-off samples. It was also found that CuCH removed other organophospurous pesticides like methyl parathion and parathion under prevailing conditions. The results indicated that CuCH could be applied for the removal of organophosphorous pesticides.

Removal of methyl parathion by surfactant-assisted soil washing and subsequent wastewater biological treatment

e aim of this work is to present an integrated process for the remediation of soils contaminated with o,o-dimethyl o-(pnitrophenyl)phosphorothioate, known as methyl parathion (MP), by surfactant-enhanced soil washing and treatment of the produced wastewaters in an aerobic-submerged bio lter. Soils containing approximately 0.4 and 13 mg/kg of MP were washed using anionic, nonionic, zwitterionic, and natural surfactants. Between 63 and 98% of the initial concentrations of MP were removed. Wastewater produced from soil washing with the addition of a natural biosurfactant, locust bean gum [0.01% (w/w)], was used for the experiments in an aerobic-submerged bio lter in which MP concentration decreased from an initial value of 0.78 mg/L up to a value of 0.05 mg/L in 6 days, indicating the feasibility of the treatment proposed. © Pesticide Science Society of Japan

Evaluation of vermicompost as a raw natural adsorbent for adsorption of pesticide methylparathion

The assessment of vermicompost (VC) as a low-cost and alternative adsorbent for the removal of the pesticide methylparathion (MP) from an aqueous medium has been investigated by batch and column experiments. Parameters related to MP adsorption, i.e. equilibrium time (61.5 min) and adsorption pH (6.8) were optimized by using Doehlert design. The initial and final MP concentrations after adsorption assays were determined by square-wave adsorptive cathodic stripping voltammetry using an electrode composed of a multiwalled carbon nanotube dispersed in mineral oil. Batch adsorption experimental data were fitted to the Langmuir and Freundlich isotherm adsorptions, and a very good fit to the Langmuir linear model, giving a maximum adsorption capacity (MAC) of 0.17 mg g−1. This result was very similar to that obtained with the column experiments. In order to evaluate the MP desorption from column packed VC, 100.0 ml of nitric acid solution (pH 3.0) has been percolated through material. No leaching of MP was observed, thus confirming the strong interaction between MP and VC. The satisfactory MAC obtained and low cost makes the VC a reliable natural material for the removal of MP from aqueous effluents.

Glucose effect on degradation kinetics of methyl parathion by filamentous fungi species Aspergilus Niger AN400

This study evaluated the glucose effect on the removal of methyl parathion by Aspergillus niger AN400. The study was conducted in two stages: toxicity tests on plates and assays in flasks, under an agitation of 200 rpm. The methyl parathion concentrations in the toxicity test ranged from 0.075 to 60 mg/L. The second stage consisted on evaluating reactors: six control reactors with methyl parathion solution; six reactors with fungi and methyl parathion, and six reactors containing fungi, methyl parathion, and glucose. The reaction times studied ranged from 1 to 27 days. Methyl parathion concentrations of up to 60 mg/L were not toxic for Aspergillus niger AN400. The first-order kinetic model served as a good representation of the methyl parathion conversion rate. The first-order kinetic constant was 0.063 ± 0.005 h-1 for flasks without addition of glucose, while a value of 0.162 ± 0.014 h-1 was obtained when glucose was added.

Removal of methyl parathion from a chinampa agricultural soil of Xochimilco Mexico: A laboratory study

Large amounts of methyl parathion are used to control pests on crops when cultivated in chinampa soils of Mexico City. The effect of adding methyl parathion on soil characteristics, CO 2 emissions, mineral N and 4-nitrophenol, a degradation product of methyl parathion, and the degradation of methyl parathion, was investigated in an aerobic incubation experiment. Treatments were sterilized and non-sterilized soil amended with or without methyl parathion at 280 mg kg −1, a concentration sometimes found in the top soil. Methyl parathion removal followed a first-order kinetic with a half-life ranging from 16 to 34 days, while small amounts of 4-nitrophenol were detected after three days. No abiotic processes affected the methyl parathion concentration and no 4-nitrophenol was formed in the sterilized soil. It was found that methyl parathion was removed rapidly from soil and less than 35 μg kg −1 4-nitrophenol was found in soil.

Removal of methyl parathion and tetrachlorvinphos by a bacterial consortium immobilized on tezontle-packed up-flow reactor

A tezontle-packed up-flow reactor (TPUFR) with an immobilized bacterial consortium for biological treatment of methyl-parathion and tetrachlorvinphos was evaluated. These organophosphate pesticides are widely used in Mexico for insect and mite control, respectively. With the aim of developing a tool for pesticide biodegradation, four flow rates (0.936, 1.41, 2.19, and 3.51l/h) and four hydraulic residence times (0.313, 0.206, 0.133, and 0.083h) were evaluated in a TPUFR. In the bioreactor, with an operating time of 8h and a flow of 0.936l/h, we obtained 75% efficiency in the removal of methyl-parathion and tetrachlorvinphos. Their adsorptions in the volcanic rock were 9% and 6%, respectively. It was demonstrated that the removal of pesticides was due to the biological activity of the immobilized bacterial consortium. We confirmed the decrease in toxicity in the treated effluent from the bioreactor through the application of acute toxicity tests on Eisenia foetida. Immobilization of a bacterial consortium using tezontle as a support is innovative and an economical tool for the treatment of mixtures of organophosphorus pesticide residues.

Removal of methyl parathion by cyanobacteria Microcystis novacekii under culture conditions

This study investigated the removal of methyl parathion by cyanobacteria Microcystis novacekii in culture conditions and evaluated toxicity in terms of EC(50) of the pesticide for the species. This is the first report on the removal and toxicity of methyl parathion for the species that is abundant and easily accessible in Brazilian lakes. The results have shown that Microcystis novacekii is capable of removing methyl parathion, an organophosphorus pesticide, from the culture medium with an extraction rate higher than 90%. Spontaneous degradation was not significant, which indicates a high efficiency level of biological removal. No metabolites of methyl parathion were detected in the culture medium at the concentration levels evaluated (0.10 to 2.00 mg/dm(3)). The mechanisms proposed to explain pesticide removal are bioaccumulation and mineralization. EC(50) for 72 h was 17.60 mg/dm(3), which is much higher than the usual concentrations in surface waters. This indicates that M. novacekii is highly tolerant of this pesticide and may represent an important bioremediation agent of contaminated environments.

Removal of Methyl Parathion in Water, by Dugesia dorotocephala

The aim of this study was to determine the efficiency of Dugesia dorotocephala on Methyl parathion removal. An initial concentration of 1.25 microg mL(-1) of MeP was used to evaluate the removal capacity of planarian. A first-order removal kinetics was obtained with a disappearance rate constant (k(r)) of 0.49 days(-1) and 69% efficiency on contaminant removal. This is significantly different (p < 0.5) from the degradation occurring in control systems, leading us to conclude that D. dorotocephala effectively removes MeP from contaminated water.

Removal of Methyl Parathion from Artificial Off-Gas Using a Bioreactor Containing a Constructed Microbial Consortium

Methyl parathion (MP), a highly toxic organophosphorus pesticide, was widely used for agriculture crop protection. During the production of MP and the process of MP-containing wastewater treatment, MP can release into the atmosphere and will do great harm to adjacent communities. A consortium comprised of an engineered microorganism and a natural p-nitrophenol (PNP) degrader was assembled for complete mineralization of MP. We genetically engineered Escherichia coli BL21 (DE3) enabling the overexpression of methyl parathion hydrolase (MPH). In addition, we isolated Ochrobactrum sp. strain LL-1 that utilized PNP, a product of MP hydrolysis, as the sole carbon, nitrogen, and energy source. The coculture effectively hydrolyzed 0.2 mM MP and prevented the accumulation of PNP in suspended culture. A laboratory-scale bioreactor containing the dual-species consortium was developed for the treatment of artificial off-gas containing MP. The bioreactor maintained over 98% of average MP removal efficiency over a 75 day period, and PNP produced from hydrolysis of MP was degraded completely, indicating that complete mineralization of MP was achieved. The strategy of linking degrading consortium to a bioreactor may provide an alternative to physicochemical abatement technologies for the treatment of waste-gas streams containing MP as well as other PNP-substituted organophosphates.

Adsorption of methyl parathion pesticide from water using watermelon peels as a low cost adsorbent

Abstract In the present studies chemically and thermally treated watermelon peels (TWMP) have been utilized for the removal of methyl parathion (MP) pesticide from water. The effect of process variables such as pH of solution, shaking speed, shaking time, adsorbent dose, concentration of solution and temperature have been optimized. Maximum adsorption (99 ± 1%) was achieved for (0.38–3.80) × 10−4 mol dm−3 of MP solution, using 0.1 g of adsorbent in 20 ml of solution for 60 min agitation time at pH 6. BET and SEM analysis have been carried out for the characterization of TWMP. Adsorption data has been analyzed by Freundlich, Langmuir and Dubinin–Radushkevich (D–R) adsorption isotherms. Lagergren, Morris–Weber and Reichenberg equations have been used for kinetic studies of adsorption process. Thermodynamic parameters ΔH, ΔS and ΔG have been calculated. Positive value of ΔH and negative value of ΔG show endothermic and spontaneous nature of adsorption respectively. The developed adsorption method has been employed to surface water samples with percent removal 99% ± 1.

Removal of methyl parathion from water by electrochemically generated Fenton’s reagent

The electro-Fenton process was used to assess the degradation of methyl parathion (MP) in aqueous solutions. This oxidation process allows the production of hydroxyls radicals which react on the organic compounds, leading to their mineralization. Degradation experiments were performed either in perchloric, sulphuric, hydrochloric and nitric acid media under current controlled electrolysis conditions at different pH. The pH effect as well as the nature of the medium (i.e., the nature of the ions present in medium) on the degradation and mineralization efficiency were studied. The mineralization of the initial pollutant was investigated by total organic carbon measurements which show a complete mineralization at pH 3 in perchloric medium. The absolute rate constant of MP hydroxylation reaction was determined as (4.20 ± 0.11) × 10 9 M −1 s −1. Complete degradation of MP and its metabolites occur in less than 45 min. Degradation reaction intermediates such as aromatic compounds, carboxylic acids and inorganic ions were identified and a mineralization pathway is proposed.

Simultaneous biodegradation of methyl parathion and carbofuran by a genetically engineered microorganism constructed by mini-Tn5 transposon

A genetically engineered microorganism (GEM) capable of simultaneous degrading methyl parathion (MP) and carbofuran was successfully constructed by random insertion of a methyl parathion hydrolase gene (mpd) into the chromosome of a carbofuran degrading Sphingomonas sp. CDS-1 with the mini-transposon system. The GEM constructed was relatively stable and cell viability and original degrading characteristic was not affected compared with the original recipient CDS-1. The effects of temperature, initial pH value, inoculum size and alternative carbon source on the biodegradation of MP and carbofuran were investigated. GEM cells could degrade MP and carbofuran efficiently in a relatively broad range of temperatures from 20 to 30 degrees C, initial pH values from 6.0 to 9.0, and with all initial inoculation cell densities (10(5)-10(7) CFU ml(-1)), even if alternative glucose existed. The optimal temperature and initial pH value for GEM cells to simultaneously degrade MP and carbofuran was at 30 degrees C and at pH 7.0. The removal of MP and carbofuran by GEM cells in sterile and non-sterile soil were also studied. In both soil samples, 50 mg kg(-1) MP and 25 mg kg(-1) carbofuran could be degraded to an undetectable level within 25 days even if there were indigenous microbial competition and carbon sources effect. In sterile soil, the biodegradation rates of MP and carbofuran were faster, and the decline of the inoculated GEM cells was slower compared with that in non-sterile soil. The GEM constructed in this study was potential useful for pesticides bioremediation in natural environment.

Poly-β-Cyclodextrins: Multifunctional Polymer Support for the Hydrolysis and Removal of Methyl Parathion

AbstractMicroparticles (32-53 μm) of cross-linked poly-β-Cyclodextrin (PCD) having a bifunctional hexyl spacer were prepared. PCD served as an insoluble robust matrix, which is chemically inert in acidic and basic media while preserving accessibility of pesticide methyl parathion (MPT) and its hydrolysis product p-nitrophenol (p-NP) to cyclodextrin cavities. The multi-utility of PCD was demonstrated as a stable biomaterial for adsorption of MPT and p-NP through inclusion phenomena and as a single unit system suitable for casting alternate enzyme/polyelectrolyte multilayers.

Silver-complexed chitosan microparticles for pesticide removal

Two types of chitosan microparticles (CMs) and their silver-complexes CMs (SCMs) were prepared using different crosslinking agents, i.e. glutaraldehyde and epichlorohydrin, in order to investigate the adsorption and release behaviors of a typical pesticide, methyl parathion (MP). The pH and concentration dependencies on Ag(I) and MP adsorptions on both the CMs and SCMs were studied. The epichlorohydrin-crosslinked CM apparently showed the superiority of Ag(I) adsorption over the glutaraldehyde-crosslinked CM, nevertheless, adsorption behavior of MP on SCM derived from each CM was observed vice versa. Release behavior of MP from the MP-loaded SCMs was also observed in aqueous acetic acid and sodium acetate buffer solutions at low pH as well as in those containing two kinds of ammonium reagents. The aqueous solutions containing ammonium thiocyanide and ammonia could be applied for MP release from the MP-loaded SCMs without Ag(I) leakage from the particles. Furthermore, from the iteration of adsorption and release experiments of MP, glutaraldehyde-crosslinked SCM provides good reusability for MP removal.

Short communication: Methylparathion degradation by Pseudomonas sp. A3 immobilized in sodium alginate beads

An organophosphate-degrading soil isolate of Pseudomonas sp. A3, immobilized at 5% (wet wt/v) cell mass in 3% (w/v) sodium alginate beads, detoxified 99% of 1 mM methylparathion in 48 h. The beads were re-usable for five batches, the sixth batch only giving 73% methylparathion removal.