Environmental Pollution ( IF 6.792 ) Pub Date : 2020-08-01 , DOI: 10.1016/j.envpol.2020.115277 Moustafa R. AbuKhadra; Mohamd Hamdey Eid; Ahmed Aly Allam; Jamaan S. Ajarem; Ahmed M. Almalki; Yasser Salama
Three types of diatomite-based adsorbents—diatomaceous earth (DE), purified diatomite (PD), and [email protected]/CaO ([email protected]) were used for adsorption decontamination of ammonium from Lake Qarun water (28.7 mg/L). The adsorption properties of the three diatomite-based adsorbents were evaluated by both batch and fixed-bed column adsorption studies. The kinetic results demonstrated removal percentages of 97.2%, 69.5%, and 100% using DE, PD, and [email protected], respectively, at a 1 g/L adsorbent dosage. The adsorption results using DE and [email protected] showed the best fitness with pseudo-first-order kinetic and Langmuir isotherm models, while the obtained results using PD demonstrate better fitness with the Freunlidich model. The recognized fitting results with the pseudo-first-order model and estimated adsorption energies demonstrated physical uptake of ammonium by DE (5.93 KJ/mol), PD (4.05 KJ/mol), and [email protected] (7.81 KJ/mol). The theoretical maximum ammonium uptake capacity of DE, PD, and [email protected] were 63.16 mg/g, 59.5 mg/g, and 78.3 mg/g, respectively. Using synthetic adsorbents in a fixed-bed column system for treating ammonium ions in Lake Qarun water resulted in removal percentages of 57.4%, 53.3%, and 62.6% using a DE bed, PD bed, and [email protected] bed, respectively, after treating approximately 7.2 L of Lake Qarun water using a bed thickness of 3 cm, a flow rate of 5 mL/min, pH 8, and the determined ammonium concentration in Lake Qarun water (28.7 mg/L). The curves demonstrated breakthrough times of 900 min, 900 min, and 960 min for the DE bed, PD bed, and [email protected] bed, respectively, with 1440 min as the saturation time. The columns’ performances also were studied based on the Thomas model, the Adams-Bohart model, and the Yoon-Nelson model.