Potential adsorption mechanisms of different bio-wastes to remove diazinon from aqueous solution

This paper investigated the isotherms, kinetics, and mechanisms of three types of bio-waste derived from agro-waste, synthesized as potential adsorbents in diazinon extraction from aqueous solution. The adsorption capacity that differentiates each of the bio-wastes were discussed. Bio-wastes were synthesized for 4 h at a temperature of 600 °C. Bio-wastes were modified by hydrofluoric acid (HF) to enhance the specific area and porosity. The SEM, BET, FT-IR, and pHpzc were used to analyse the characteristics of the bio-wastes. Experimental results showed the different BET specific surface areas ranged from 67.42 to 402.43 m 2 .g −1 of each bio-waste. Meanwhile, SEM showed that bio-wastes possessed an intricate pore network comprising micropores and narrow mesopores. The pore volume disseminations in the size of the micropores (<2 nm) and narrow mesopores (2-20 nm) of bio-wastes in the range of 16.88-21.24% and 56.57-69.22%, respectively. Solution pH at 4 carried out the highest removal efficiency of diazinon. Langmuir isotherm model showed the best fit to the experimental adsorption data. The maximum adsorption capacities of bio-wastes ranged from 8.60-15.83 mg.g −1 . The pore filling and chemical adsorption participated in the adsorption mechanisms of diazinon and other bio-wastes.