Single and binary component adsorption of endocrine disrupting chemicals from aqueous solutions using calcium alginate/apricot stone-activated carbon composite beads

Abstract

Alginate gel (A) and activated carbon prepared from apricot stone (AC) were combined to prepare activated carbon alginate beads (A-AC) adsorbent and used to remove bisphenol A (BPA) and 2,4,5-tri-chlorophenol (TCP) from solution in single and binary system. The zero point charge determination (pHpzc), the scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were carried out. The effects of pH solution (2–11), temperature (15°C, 25°C, 35°C, and 45°C), initial concentration (15–400 mg/L) and contact time were investigated. The adsorption processes fitted well with the pseudo-second-order kinetic model and Langmuir isotherm. Results showed that the maximum adsorption capacities of A-AC for the adsorption of BPA and TCP in single system are 419.3 and 444.3 mg/g at 25°C, respectively. In the binary system, a decrease was observed at the adsorbed amount to 291.2 mg/g for BPA and 430.2 mg/g for TCP. The thermodynamic parameters confirmed that the adsorption reaction was spontaneous and endothermic in nature. Desorption tests showed that the removal efficiency of A-AC for BPA and TCP decreased slightly after six regeneration cycles and were maintained at 83.2% and 77.6%, respectively. The results suggest that the use of A-AC beads is a feasible strategy for the removal of BPA and TCP.