Activated Carbon Synthesized from Nypa fruticans and Areca catechu by Microwave Method as Efficient Adsorbent for the Removal of Chloramphenicol

Abstract

This work employed the microwave-assisted method to prepare activated carbons from the byproducts of Areca catechu (ACAC) shells and Nypa fruticans (ACNF) nut shells. The results show that the materials have a rough surface like a coral reef and contains the characteristic functional groups such as O-H, C=O, C=C, C-O with an amorphous structure. Surface area and pore size were also evaluated with ACAC of 195.93 m² g^-1 and ACNF of 514.91 m² g^-1. The adsorption isotherms predict the size of the pores as small mesopores. The factors affecting ciprofloxacin adsorption using derived activated carbon were also evaluated. For ACAC, the best optimized adsorption conditions were contact time 90 min, temperature 40 ºC, pH 6, dosage 2 g L^-1, concentration 80 mg L^-1, whereas for ACNF, the best adsorption conditions were contact time 90 min, temperature 40 ºC, pH 4, dosage 1 g L^-1, concentration 80 mg L^-1. The results show that activated carbon samples ACAC and ACNF follow the pseudo-second-order (PSO) kinetic model, Elovich kinetic model, Dubinin-Radushkevich (D-R) and Temkin isotherms. The Langmuir model was used to record the maximal adsorption capacities of ACAC and ACNF for ciprofloxacin, which were 57.60 mg g^-1 and 67.59 mg g^-1, respectively. The adsorption process occurs by diffusion with chemisorption interactions on a homogeneous surface for ACAC and heterogeneous surface for ACNF.