Chlorine Removal from Water by Biochar Derived from Various Food Waste Natural Materials

Abstract

The aim of this paper was to investigate the effectiveness of pyrolyzed low-cost food waste natural materials from the food industry on the removal of chlorine from water. Biochar was produced after pyrolysis at 850 oC from malt spent rootlets (MSR), walnut shells, and apricot, olive, carob and grape kernels. The biochars were characterized for their surface area, microporosity, functional groups and pH. Continuous flow column experiments were conducted at varying flow rates to evaluate the efficiency of biochars to remove free and total chlorine. The initial free and total chlorine concentrations in water fed to the columns were 2.0 and 2.2 mg/L, respectively. The chlorine removal of free and total chlorine of all materials tested ranged from 76 to 92% and 80 to 95%, respectively, with the MSR exhibiting the highest removal. MSR biochar was subjected to the highest cumulative water volume passed through the column (162 L/g) and exhibited the highest total chlorine removal capacity (6 to 330 mg/g). Olive kernel also reached high chlorine removal (99%), while apricot kernel, grape kernel, carob seed and pulp presented poor chlorine removals.