Utilization of organic by-products for the removal of organophosphorous pesticide from aqueous media

Low-cost materials as vehicles for pesticides in aquatic media: a review of the current status of different biosorbents employed, optimization by RSM approach

Water contamination by pesticides is increasing dramatically due to population growth and the extensive use of pesticides in agriculture, leading to grave environmental and health concerns. Thus, efficient processes and the design and development of effective treatment technologies are required due to the enormous demand for fresh water. The adsorption approach has been widely used to remove organic contaminants such as pesticides because of its performance, less expense, high selectivity, and simplicity of operation compared to other treatment technologies. Among alternative adsorbents, biomaterials abundantly available for pesticide sorption from water resources have attracted the attention of researchers worldwide. The main objective of this review article is to (i) present studies on a wide range of raw or chemically modified biomaterials potentially effective in removing pesticides from aqueous media; (ii) indicating the effectiveness of biosorbents as green and low-cost materials for removing pesticides from wastewater; and (iii) furthermore, report the application of response surface methodology (RSM) for modeling and optimizing adsorption.

Eating with peel or not: Investigation of the peel consumption situation and its nutrition, risk analysis, and dietary advice in China

Nutritious, balanced, tasty and easy to eat, fruit is an indispensable health food for consumers. With consumers' increasing respect for the concept of health, green and nutrition, the peel, which has higher nutritional value compared to the pulp, is gradually being emphasized in the consumption process. The suitability of fruit peels for consumption is influenced by various factors, such as the amount of pesticide residues, nutrient content, ease of peeling, and fruit texture, but there is a lack of relevant studies to guide consumers' scientific intake of fruit peels. This review first investigated chineses consumers consumption of common fruits with peels, especially eight fruits that are controversial in terms of whether to consume them with peels, and the results showed that whether people consume peels depends mainly on their nutritional value and pesticide residues. Based on this, the paper discusses the common methods of pesticide detection and removal from fruit peels, as well as the nutrients contained in different fruit peels and their physiological activities, if the peels usually have stronger antioxidant, anti-inflammatory and anti-tumor activities than the pulp. Finally, reasonable dietary recommendations are made on whether fruits should be consumed with their peels, with a view to guiding chineses consumers towards scientific consumption and provide theoretical basis for relevant research in other countries.

Synthesis of monolith silica anchored graphene oxide composite with enhanced adsorption capacities for carbofuran and imidacloprid

Highly efficient adsorbent was prepared for the removal of carbofuran and imidacloprid pesticides from wastewater. The silica monolith anchored graphene oxide composite was synthesized by the modified Fischer esterification protocol. The composite showed improved adsorption capacity for the removal of pesticides from wastewater. Graphene oxide was synthesized using the modified Hummer's method, while the silica monolith was prepared via sol-gel method. The composite was characterized via X-ray diffraction, Fourier transform infra-red, Brunauer Emmett and Teller (BET/BJH) analysis, zeta potential, and FESEM imaging. Different adsorption parameters such as pH, contact time, adsorbate and adsorbent concentration, and temperature were optimized for the adsorption of pesticides. The equilibrium and kinetic models were applied to the adsorption process of the pesticides. Qe of the composite as found to be 342.46 mg g^-1 for imidacloprid and 37.15 mg g^-1 for carbofuran. The adsorption process followed the pseudo 2nd order kinetic model for carbofuran (R²~0.9971) and imidacloprid (R²~0.9967). The Freundlich isotherm best fitted to the adsorption data of the pesticides with R² value of 0.9956 for carbofuran and 0.95 for imidacloprid. The resultant adsorbent/composite material came out with very good results for the removal of pesticides.

Use of Green Chemistry for Amputation of Chromium Ions from Wastewater by Alkali-Treated Composts of Fruit Peels in Economical Way

In this work, removal of chromium (VI) using alkali-treated composted peels of lemon (Citrus limonum), mango (Mangifera indica), water melon (Citrullus lanatus), and melon (Cucumis melo) has been studied in batch mode. Physico-chemical characteristics of each sorbent material were determined together with their subsequent characterization by scanning electron microscopic, FTIR, and TGA. The selected sorbent materials were chemically modified using nitric acid and sodium hydroxide solutions. Adsorption efficacy of the selected sorbent materials for Cr (VI) was investigated by optimizing different parameters. The most favorable conditions were as follows: adsorbent dosage = 1.2 g/50mL, pH = 4.0, agitation speed = 170 rpm, 60 minutes = contact time, and temperature = 313°K. Base-treated adsorbents were found to be better adsorbents as compared to the acid treated form which in turn are better than raw adsorbents (adsorbents without chemical modification). Overall, the chosen sorbents removed Cr (VI) in the range of 53.62–96%, whereas the maximum sorption is with base-treated water melon peels (BWMP), that is, 95.98%. The kinetic studies discovered that the results fitted with pseudo-second-order model. Thermodynamic parameters also support that under optimal conditions, all the selected sorbents specifically base-treated sorbents are good enough for the elimination of Cr (VI) ions in an eco-friendly way.

The Potentiality of Rice Husk-Derived Activated Carbon: From Synthesis to Application

Activated carbon (AC) has been extensively utilized as an adsorbent over the past few decades. AC has widespread applications, including the removal of different contaminants from water and wastewater, and it is also being used in capacitors, battery electrodes, catalytic supports, and gas storage materials because of its specific characteristics e.g., high surface area with electrical properties. The production of AC from naturally occurring precursors (e.g., coal, biomass, coconut shell, sugarcane bagasse, and so on) is highly interesting in terms of the material applications in chemistry; however, recently much focus has been placed on the use of agricultural wastes (e.g., rice husk) to produce AC. Rice husk (RH) is an abundant as well as cheap material which can be converted into AC for various applications. Various pollutants such as textile dyes, organic contaminants, inorganic anions, pesticides, and heavy metals can be effectively removed by RH-derived AC. In addition, RH-derived AC has been applied in supercapacitors, electrodes for Li-ion batteries, catalytic support, and energy storage, among other uses. Cost-effective synthesis of AC can be an alternative for AC production. Therefore, this review mainly covers different synthetic routes and applications of AC produced from RH precursors. Different environmental, catalytic, and energy applications have been pinpointed. Furthermore, AC regeneration, desorption, and relevant environmental concerns have also been covered. Future scopes for further research and development activities are also discussed. Overall, it was found that RH-derived AC has great potential for different applications which can be further explored at real scales, i.e., for industrial applications in the future.

Removal of Acidic Dyes from Aqueous Media Using Citrullus Lanatus Peels: An Agrowaste-Based Adsorbent for Environmental Safety

In this work, removal of fluorescein and eosin dyes using common agrowaste, i.e., peels of water melon (Citrullus lanatus) (WMP), has been studied in the batch mode. The sorbent material (WMP) was characterized by using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. The sorbent was chemically modified by subjecting it to 0.1 N HNO3 and 0.1 N NaOH solutions. Different parameters such as sorbent dose, pH, temperature, and agitation speed were optimized to investigate the sorbent efficiency for fluorescein and eosin dyes. Among three forms (raw, base-treated, and acid-treated), the base-treated form exhibited higher removal efficiency, followed by acid-treated and then the raw form. Generally, range for the removal of fluorescein and eosin was found to be 48.06–88.08% and 48.47–79.31%, respectively. Mathematical modeling of sorption data by Langmuir and Freundlich sorption isotherms and thermodynamic investigations were carried out to check the suitability of these agrowaste materials on bulk scale. The promising results concluded that peel of water melon (common agrowaste) can be potentially utilized for the removal of toxins.

A review on removal of organophosphorus pesticides in constructed wetland: Performance, mechanism and influencing factors

The residues of organophosphorus pesticides (OPPs) have been widely detected in rivers, the gulf, and even groundwater and drinking water, which may pose a serious threat to aquatic ecosystems and human health. Compared to other treatments, constructed wetlands (CWs) have been demonstrated to be a cost-effective alternative risk mitigation strategy for non-point-source pesticide pollution. This review summarizes 32 studies related to the remediation of OPPs in 117 CWs during 2001-2017 worldwide. The performances, mechanisms and influencing factors in the studies are comprehensively and critically reviewed in this paper. Overall, the OPPs were efficiently removed with an efficiency up to 87.22 ± 16.61%. The removal efficiency, differences and related reasons among different types of CWs in developed and developing countries and the different types of OPPs in CWs are well-evaluated in detail. In addition, the main processes for OPPs removal in CWs involve phytoremediation (plant uptake, phytoaccumulation, phytovolatilization and phytodegradation), substrate adsorption or sedimentation, and biodegradation. Based on the quantitative analysis by mass balance, for water-soluble pesticides, the dominant removal process was via microbiological degradation. This result was in contrast to findings obtained with hydrophobic OPPs, for which the dominant processes were biodegradation and sorption by substrate. Therefore, the behavior of microbial transformation prevails. Additionally, the presence of plants can facilitate the elimination of OPPs in CWs, promoting the process by an average percentage of approximately 6.19 ± 9.46%. Statistical analysis shows that loading of inlet OPPs is the largest limiting factor and that the HRT and T are the most significant parameters that influence the efficiency of trapping OPPs in CWs. Simultaneously, we can also obtain suitable parameters for the design and operation of CWs. This review promotes further research on plant-microbe joint combined remediation and examines the different behaviors of water-soluble and hydrophobic OPPs in CWs.

Kinetic and isotherm error optimization studies for adsorption of atrazine and imidacloprid on bark of Eucalyptus tereticornis L

The aim of this study was to establish the bark of Eucalyptus tereticornis L. (EB) as a low cost bio-adsorbent for the removal of imidacloprid and atrazine from aqueous medium. The pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich and intra-particle diffusion (IPD) models were used to describe the kinetic data and rate constants were evaluated. Adsorption data was analysed using ten 2-, 3- and 4-parameter models viz. Freundlich, Jovanovic, Langmuir, Temkin, Koble-Corrigan, Redlich-Peterson, Sips, Toth, Radke-Prausnitz, and Fritz-Schluender isotherms. Six error functions were used to compute the best fit single component isotherm parameters by nonlinear regression analysis. The results showed that the sorption of atrazine was better explained by PSO model, whereas the sorption of imidacloprid followed the PFO kinetic model. Isotherm model optimization analysis suggested that the Freundlich along with Koble-Corrigan, Toth and Fritz-Schluender were the best models to predict atrazine and imidacloprid adsorption onto EB. Error analysis suggested that minimization of chi-square (χ(2)) error function provided the best determination of optimum parameter sets for all the isotherms.

Removal of xenobiotics from effluent discharge by adsorption on zeolite and expanded clay: an alternative to activated carbon?

Xenobiotics such as pesticides and pharmaceuticals are an increasingly large problem in aquatic environments. A fixed-bed adsorption filter, used as tertiary stage of sewage treatment, could be a solution to decrease xenobiotics concentrations in wastewater treatment plants (WWTPs) effluent. The adsorption efficiency of two mineral adsorbent materials (expanded clay (EC) and zeolite (ZE)), both seen as a possible alternative to activated carbon (AC), was evaluated in batch tests. Experiments involving secondary treated domestic wastewater spiked with a cocktail of ten xenobiotics (eight pharmaceuticals and two pesticides) known to be poorly eliminated in conventional biological process were carried out. Removal efficiencies and partitions coefficients were calculated for two levels of initial xenobiotic concentration, i.e, concentrations lower to 10 μg/L and concentrations ranged from 100 to 1,000 μg/L. While AC was the most efficient adsorbent material, both alternative adsorbent materials showed good adsorption efficiencies for all ten xenobiotics (from 50 to 100 % depending on the xenobiotic/adsorbent material pair). For all the targeted xenobiotics, at lower concentrations, EC presented the best adsorption potential with higher partition coefficients, confirming the results in terms of removal efficiencies. Nevertheless, Zeolite presents virtually the same adsorption potential for both high and low xenobiotics concentrations to be treated. According to this first batch investigation, ZE and EC could be used as alternative absorbent materials to AC in WWTP.

Organic xenobiotics removal in constructed wetlands, with emphasis on the importance of the support matrix

Constructed wetlands (CWs) are increasingly popular as an efficient and economical alternative to conventional wastewater treatment processes for removal, among other pollutants, of organic xenobiotics. In CWs, pollutants are removed through the concerted action of their components, whose contribution can be maximized by careful selection of those components. Specifically for non-biodegradable organic pollutants, the materials used as support matrix of CWs can play a major role through sorption phenomena. In this review the role played by such materials in CWs is examined with special focus on the amount of research that has been conducted to date on their sorption properties relatively to organic compounds. Where available, the reports on the utilization of some of those materials on pilot or full-scale CWs are also recognized. Greatest interest has been directed to cheaper and widely available materials. Among these, clays are generally regarded as efficient sorbents, but materials originated from agricultural wastes have also gained recent popularity. Most available studies are lab-scale batch sorption experiments, whereas assays performed in full-scale CWs are still scarce. However, the available lab-scale data points to an interesting potential of many of these materials for experimentation as support matrix of CWs targeted for organic xenobiotics removal.

Banana peel as an adsorbent for removing atrazine and ametryne from waters

The feasibility of using banana peel for removal of the pesticides atrazine and ametryne from river and treated waters has been demonstrated, allowing the design of an efficient, fast, and low-cost strategy for remediation of polluted waters. The conditions for removal of these pesticides in a laboratory scale were optimized as sample volume = 50 mL, banana mass = 3.0 g, stirring time = 40 min, and no pH adjustment necessary. KF(sor) values for atrazine and ametryne were evaluated as 35.8 and 54.1 μg g(-1) (μL mL(-1)) by using liquid scintillation spectrometry. Adsorption was also evaluated by LC-ESI-MS/MS. As quantification limits were 0.10 and 0.14 μg L(-1) for both pesticides, sample preconcentration was not needed. Linear analytical curves (up to 10 μg L(-1)), precise results (RSD < 4.5%), good recoveries (82.9-106.6%), and a > 90% removal efficiency were attained for both pesticides. Water samples collected near an intensively cultivated area were adequately remedied.

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

PURPOSE

Removal of malathion from agricultural runoff was studied using novel copper-coated chitosan nanocomposite (CuCH)-a biopolymeric waste obtained from marine industry.

METHODS

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.

RESULTS

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.

CONCLUSIONS

The results indicated that CuCH could be applied for the removal of organophosphorous pesticides.

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.

Removal of triazophos pesticide from wastewater with Fenton reagent

The catalytic oxidation of triazophos pesticide from wastewater using Fenton reagent was investigated at bench-scale in this study. Synthesized wastewater and actual industrial triazophos pesticide wastewater taken from a pesticide company were examined sequentially. The COD values of the synthesized and actual industrial triazophos pesticide wastewater samples were 3242 and 3418 mg/L, respectively, and the triazophos concentration in these wastewater samples was 0.06% by weight. The effects of reaction conditions including the dosages of FeSO(4).7H(2)O and H(2)O(2), the pH value of the environment, and the stirring time on COD removal from the synthesized wastewater were evaluated, and COD removal efficiency of 96.3% with a corresponding effluent COD value of 120 mg/L was achieved under optimal reaction conditions of a pH value of 4, a dosage of 2.5 g/L of FeSO(4).7H(2)O and 100 mL/L of 30% H(2)O(2) solution, and a stirring time of 90 min. Results also showed that 71.2% of nitrogen and 68.5% of phosphorous in the synthesized triazophos wastewater were converted to NO(3)(-) and PO(4)(3-), respectively, at the optimal reaction condition. When the actual industrial wastewater was treated at a pH value of 4, COD removal efficiency of 85.4% with a corresponding effluent COD value of 499 mg/L were reached at optimal condition of a dosage of 5.0 g/L of FeSO(4).7H(2)O and 75 mL/L of 30% H(2)O(2) solution, and a stirring time of 90 min. The results of this study can be referred for the design of a treatment process for the actual industrial triazophos wastewater.