Ternary metal-organic framework/multi-walled carbon nanotube/iron oxide nanocomposite for removal of butachlor pesticide

Abstract

Background: Butachlor (BUT) as an organochlorine pesticide (OCP) that prevents weeds from growing has been used in the agriculture field. It remains in the environment for a long time and causes mutagenicity and cancer. Results: In the current study, magnetic multi-walled carbon nanotube with zeolitic imidazolate frameworks-67 (Fe3O4–MWCNT–ZIF67) was used as adsorbent to remove BUT from the aqueous solution. The characteristics and the chemical composition of the adsorbent were evaluated using FE-SEM, TEM, MAP, EDX, FTIR, BET, TGA and VSM. The response surface methodology (RSM) as a method for the design of experiment was applied to optimize variables such as the initial concentration of BUT, adsorbent dosage, contact time and temperature in the batch experiment by central composite design (CCD). The optimum adsorption condition predicted by RSM was pH = 4.5, initial concentration = 5.75 ppm, dosage = 0.07 g and contact time = 95 min. The results showed that maximum removal efficiency for the butachlor is 86%. Conclusions: Different adsorption isotherms were evaluated using adsorption equilibrium data and results showed that Temkin model has the best compatibility with the experimental data. In addition, the adsorption kinetics data were closer with pseudo-second-order model. Thermodynamic study showed that the adsorption process was spontaneous, endothermic and physical. This composite can be effectively used for the remediation/clean-up of groundwater and agricultural run-off water which are contaminated with harmful pesticides. Graphical Abstract: [Figure not available: see fulltext.].