Fermented Corn Stalk for Biosorption of Copper(II) from Aqueous Solution

Abstract

Corn stalk is the amplest and inexpensive organic material in Heilongjiang province, China. This resource is vicious, causing pollution of the environment. In this present study, an adsorbent is prepared by corn stalk fermentation with Aspergillus niger. The fermentative effects of water content ratio, initial pH medium, temperature, and time were addressed. The analysis of factors and orthogonal experiments revealed that the optimum conditions of producing cellulose were solid-liquid ratio of 1 : 5, temperature 28°C, initial pH, and 72 hours. The modification mechanism was investigated by using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The biosorption capacity of fermented corn stalk was better than that of raw corn stalk under identical conditions, and this improvement can be ascribed to the enzyme system secretion by A. niger under changing the surface properties of the raw corn stalk. Some of the hydroxyl and carboxyl groups are bounded by cellulose which became free hydroxyl and carboxyl groups with a high ability after adsorption of heavy metals.