Sulfonated Corn Stalk Enhanced Hydrogel Adsorption for Heavy Metal from Metal Mine Gallery Effluent

Abstract

There are various of abandoned metal mines in China, and a considerable amount of heavy metal contaminated water is generated through water-rock interactions and accumulated within metal mine gallery. Therefore, the effective removal of heavy metals from metal mine gallery effluent holds significant importance. In this study, sulfonated corn stalk (SCS) and acrylic acid was used to prepare the double network hydrogel SCS-gel. The maximum allowable compression force for the SCS-gel was about 3 times than that of raw hydrogel. The SCS-gel exhibited a stable adsorption capacity within the pH range from 2.0 to 6.0. The maximal adsorption capacities of Pb2+ and Cu2+ on the SCS-gel were 111.6 and 370.2 mg/g, respectively. The functional groups of -OH, C-O, C=O, COOH, and -SO3- were participated in the adsorption process through coordination and electrostatic interactions. The SCS-gel exhibited promising reusability as the adsorption efficiency for Pb2+ and Cu2+ remained at approximately 100% within 10 cycles of adsorption-desorption. The SCS-gel had an excellent removal efficiency for Pb2+ (99.8%), Cu2+ (99.1%), Mn2+ (97.4%), Zn2+ (98.8%), and Al3+ (95.7%) form actual metal mine gallery effluent by dosage of 5 g/L with the initial concentrations of Pb2+, Cu2+, Mn2+, Zn2+, and Al3+ were 4.352, 29.20, 13.02, 7.016, and 30.47 mg/L, respectively. In the fixed-bed experiments, the Thomas model has a good description for the breakthrough curves of these heavy metals. These results confirmed the possibility of adopting SCS ethers for hydrogel fabrication and verified its great potential for the practical application for the removal of heavy metals from metal mine gallery effluent.

Keywords: Sulfonated corn stalk, Hydrogel, Adsorption, Heavy metals, Metal mine gallery effluent