Treatment on thiodicarb in pesticide wastewater with walnut shells-derived carbon and its improved modification: adsorption behavior
Haifeng Bai, Bin Wang, Dilinuer Talifu, Abulikemu Abulizi, Mailikezhati Maihemuti
Abstract
Abstract The health problems caused by water pollution cannot be ignored, and the contribution of pesticides to water pollution has also become increasingly unignorable. The modified semi-coke as an adsorbent for reducing pesticide pollution to water was obtained from activated semi-coke which was modified by nitric acid (HNO3). The semi-coke was obtained by carbonization using 60 mesh walnut shell powder. After acid–base deashing, the semi-coke is dipped into zinc chloride (ZnCl2) solution to obtain activated semi-coke. Through BET analysis, the specific surface areas of semi-coke, activated semi-coke and modified semi-coke were 26.8 m2/g, 243.9 m2/g, and 339.6 m2/g respectively. An extremely high adsorption capacity of the adsorbents which is used to treat wastewater was achieved. The optimum adsorption conditions for modified semi-coke on thiodicarb solution were 30 mg/L of thiodicarb solution, adsorbent dosage of 0.01 g, adsorption temperature of 25 °C and adsorption time of 90 min. The optimum adsorption amount of 29.54 mg/gsor was achieved (sor is the abbreviation for sorbent). Moreover, through kinetics study, the result manifests that the modified semi-coke adsorption process is more fitted to the second-order kinetic model. This study provided a research implication theoretically for the treatment of pesticides in water.