Study on adsorption of ammonium and nitrate in wastewater by modified biochar

This study investigates the prepared rice husk biochar (RHB) and Mg/[email protected] biochar (MCB) microstructural, morphological, and nitrate adsorption capacity, owing to the increased concentration of nitrate ions in industrial wastewater that lead to serious environmental problems. In this study, biochar was prepared from agricultural waste, and the co-precipitation method was integrated to prepare Mg/Ca-rich layered double hydroxides (Mg/Ca-LDHs). The prepared biochar physicochemical characteristics were analyzed using XRD, FESEM, EDS, BET, and IC. Here we further investigated the influence of pyrolysis temperature and different concentrations (Mg, Ca) LDHs coatings. This study found that the pyrolysis temperature reduces the biochar yield percentage from 44.5 to 30.2 %. The biochar pores are shown in a honeycomb shape, and the diameter of the pores is about 3–5 μm. In addition, the obtained biochar pores seemed to be more fragmented as the Mg/Ca ratio gradually increased. The surface area of biochar increased with the increase in the Mg/Ca ratio, and the specific surface area of 3:1 and 4:1 Mg/Ca-LDHs ratio was the highest, reaching about 288–308 cm2/g. The biochar LDHs with a 3:1 Mg/Ca-LDHs ratio can effectively adsorb nitrate ions in water, and the LDHs maintain a stable state during the adsorption process.