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Abstract Diazinon is one of the most commonly used organophosphorus pesticides in agricultural activities, and its access to groundwater and surface waters damages the animal and plant environments. This study aimed to evaluate the applicability of the adsorption process for the removal of organophosphorus diazinon pesticide from water using multi-wall carbon nanotubes. Specifications of multi-walled carbon nanotubes were determined using FTIR, SEM, TEM and BET technologies. The effects of different parameters of pH (4 and 7), contact time (1–15 min), pesticide concentration (0.3, 0.5 and 1 mg/L) and multi-walled carbon nanotubes' dose (0.1 and 0.3 g/L) were evaluated on the process of removing diazinon by multi-walled carbon nanotubes. Based on the experimental data obtained in this study, maximum removal of diazinon (100%) from water by multi-wall carbon nanotubes are the initial concentration of diazinon (0.3 mg/L), 0.1 g/L concentration of nano-adsorbent at both pH of 4 and 7 at the contact time of 15 min. The results of the study showed that multi-wall carbon nanotubes can be used as effective and high efficient for complete removal of diazinon pesticides from aqueous solutions. Highlights • Diazinon is a serious threat to human health due to its effect on central nervous system. • Diazinon adsorption on multi-walled carbon nanotubes were conducted in a batch reactor. • Residual amount of diazinon poison in water samples was determined using TLC. • The surface morphology of MWCNs was determined by SEM and TEM. • The highest diazinon removal efficiency at pHs= 4 and 7 at 15 min contact time was 100%. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the applicability of the adsorption process for the removal of organophosphorus pesticide malathion 57% from water by using multi-walled carbon nanotubes (MWCNTs). The impact of various experimental conditions such as pH, quantity of adsorbent, concentration of pesticides, contact time and temperature was studied and optimized for the maximum removal of malathion. Unlike conventional optimization, a limited number of experiments (26 steps) were performed in a cost-effective manner for different independent variables such as MWCNTs concentration (0.1–0.5 g/L), the malathion (57%) concentration (6 mg/L and 10 mg/L), contact time (2–30 min) and pH (neutral range). Based on the experimental data obtained in a lab-scale batch study, a three-factor response surface modeling (RSM) approach was implemented in order to optimize the conditions for maximum removal of malathion, and compare experimental results with standardized malathion samples. The optimized conditions to achieve the maximum removal of malathion (100%) were determined to be a malathion concentration of 6 mg/L, an initial MWCNTs concentration of 0.5 g/L, and a contact time of 30 min. Findings of this study clearly indicated that 100% of the malathion could be cost-effectively removed by MWCNTs in conditions predicted by the proposed optimization methodology. [ABSTRACT FROM AUTHOR]