Low cost arsenic removal from aqueous solution by adsorption

Abstract

This paper deals with arsenic removal from water by adsorption with unconventional materials: natural materials (zeolite, bentonite, sepiolite, limonite, pyrolusite), waste materials (waste iron slag, waste sand filter) and modified materials (neutralized waste iron slag, iron(III)-hydroxide coated sand and activated carbon). Under the same conditions are investigated commercial sorbents to compare results. Arsenic removal by adsorption with unconventional materials is investigated in the batch reactor. The best results in batch reactor are obtained with waste materials. Waste iron slag and waste filter sand exhibited equilibrium sorption capacities of 50 μg/g and 30 μg/g, respectively, which is nearly equal to values obtained for the commercial sorbents. Due to the high content of CaO waste iron slag increases significantly water pH (pH=11). In order to minimize its deteriorating impact on the initial water quality, the waste iron slag was neutralized. The new, modified waste iron slag exhibited the highest sorption capacity, 55.

U ovom radu su prikazani rezultati istraživanja efikasnosti uklanjanja arsena iz vode sorpcijom na nekonvencionalnim materijalima: prirodnim (zeolit, bentonit, sepiolit, limonit, piroluzit), otpadnim (otpadna šljaka, otpadni filtarski pesak) i modifikovanim (modifikovana otpadna šljaka, kvarcni pesak i aktivni ugalj impregnisani gvožđe(III)-hidroksidom). Pod istim uslovima paralelno su ispitivani komercijalni sorbenti radi poređenja rezultata. Uklanjanje arsena iz vode sorpcijom je ispitivana u šaržnom sistemu Najbolji rezultati u šaržnom sistemu dobijeni su sa otpadnim materijalima: za otpadnu šljaku i 30 μg/g za otpadni filtarski pesak (za Co=0,5 mg/L), što je u nivou vrednosti koje su dobijene za komercijalne sorbente za uklanjanje arsena. Zbog visokog sadržaja CaO, otpadna šljaka značajno povećava pH vrednost vode (pH= 11). Neutralizacijom otpadne šljake dobijen je nov materijal, modifikovana otpadna šljaka, većeg sorpcionog kapaciteta: 55.