Facile synthesis of mesoporous active carbon from the valorisation of biomass waste and assessment of sequester efficiency of arsenic (As) from water

Abstract

In this study, Phoenix dactylifera frond active carbons (PDFACs) were prepared using a low-cost biomass source through zinc chloride (ZnCl2) activation for the efficient elimination at batch scale, of the environmentally hazardous component arsenic (As) from polluted water. The influence of different factors including activation temperature, impregnation ratio, and impregnation time on the pore volumes, surface areas, and carbon yields of PDFACs were investigated. The PDF, PDF charcoal (PDFC) and PDFACs were characterized through thermogravimetric analysis (TGA), BET surface area (N2 adsorption-desorption), pore size distributions (PSD), SEM, FTIR, Energy-dispersive X-ray spectroscopy (EDX), and Transmission electron microscopy (TEM) analysis demonstrated successful modification in porosity and surface morphology. The maximum BET surface area of 1677 m2/g (1666 m2/g mesopore, 11 m2/g micropore surface area) and 0.665 cm3/g total pore volume were achieved at optimum synthesis condition of 4:5 impregnation ratio, 400 °C activation temperature, and 24 h soaking time. The impregnating ratio, impregnation time and activating temperature were found to have an inverse relationship with the yield of PDFACs. The impact of pH, sorbent dosage, As(V) concentration, contact time, temperature and agitation speed were inspected in batch experiments for As(V) adsorption efficiency by PDFAC. A maximum extraction efficiency 97% of As(V) was attained at optimal working conditions of 1.5 g dosage of PDFAC, initial concentration of As(V) 10 mg L−1, 120 min contact time, pH 6.0 and agitation speed 200 rpm at temperature 25 °C. The adsorption kinetic data fit the pseudo second order kinetic model well and the sorption data fit both Langmuir and Freundlich equations with little deviation in the r2 values. Research indicated that PDFAC derived from biomass wastes by ZnCl2 activation was found to be promising and feasible material for the elimination of As(V) from the aquatic environment.