Immobilization of nickel ions into stable crystal structures as a promising way for their removal from wastewater

Abstract

Environmental pollution is increasing day by day due to industrial activities. Heavy metals are pollutants of special concern due to their toxicity, persistence, and bioaccumulation in nature. Nickel is a heavy metal that is mostly used in industries because of its anticorrosion behavior. As a consequence, nickel ions are present in the wastewater from mining, electroplating, battery manufacturing and metal finishing industries. Nickel ions are nonbiodegradable, and as such, they are present in surface water. Their high concentrations can have a dangerous impact on human health and aquatic life. In this work, a promising method for the removal of Ni ions from wastewater and their incorporation into a stable crystal structure was described. Ni-exchanged form of LTA zeolite was prepared by the standard procedure of ion exchange. After the ion exchange, powder samples were heated at temperatures of 900 to 1300 ºC in order to obtain a stable crystal structure of Ni-spinel, NiAl2O4. XRF analysis was used to study ion exchange efficiency. Characterization of raw as well as thermally treated powder samples of Ni-exchanged LTA zeolite was conducted by XRPD, DTA/TG, FT-IR and SEM analysis.