Preparation of modified Chinese medical stone and its performance on the removal of low-concentration ammonium from water

Abstract

The ammonium ion occurrence in excess consequences in the adverse effects on the ecosystem, and human health. The experiment was conducted using the Chinese medical stone to remove ammonium ion from the water. The Chinese medical stone was modified by citric acid monohydrate and designed to identify the ammonium ion uptake capacity by the MMS and focused on evaluating the adsorption and kinetics isotherm, modifier’s concentration, contact time and initial concentration effects on MMS performance. The modification process was well-appointed by mixing and shaking at 180 rpm; at 60 °C; for eighth, at mixing ratio 1:20 of the UMMS with 0.2 mol concentration of citric acid monohydrate solution. The optimum adsorption performance was determined using Beaker sequence batch test method. The SEM micrographs; BET and FTIR of UMMS and MMS tests have undertaken and evaluated. The result showed that the maximum adsorption amount of MMS to ammonium ions was 5.38 mg/g at 50 mg/L ammonium ion concentration by the experiment, and the qe max was 3.5 mg/g from Langmuir equation. The ammonium adsorption by the MMS had fitted for both the Langmuir isotherm and the Freundlich isotherm models and also adapted to the kinetic parameter pseudo-second-order model shows a superior expectation of the sorption kinetics.