Adsorptive Decontamination of Water Containing Fluoride using Waste Material

Department of Chemical Engineering, National Institute of Technology Durgapur, Durgapur-713 209, West Bengal, India Environmental Engineering Group, CSIR-Central Mechanical Engineering Research Institute, Durgapur-713 209, West Bengal, India E-mail: susmita.dutta@che.nitdgp.ac.in Manuscript received online 04 June 2020, revised and accepted 20 September 2020 In the present study, batch experiments were performed with broken earthen tea cups which are found abundantly as waste material at the road side tea shops. Since these tea cups are made of mud or clay, they do not have any adverse effect of environment. Further, by using these broken tea cups, solid disposal problems are minimized. Several process parameters such as particle size (0.1-0.62 mm), contact time (0.5-10 h), pH (4.5-8.5), adsorbent dose (10-60 gL-1), stirring speed (30-150 rpm), and initial fluoride concentrations (2-12 mgL-1) were varied during batch study and found that the said waste material had good fluoride removal efficiency. At pH 4.5, initial fluoride concentration of 10 mgL-1, particle size of 0.10 mm, adsorbent dose of 50 gL-1 and stirred speed of 120 rpm clay adsorbent showed 75% fluoride removal. Characterizations of the adsorbent were done. Adsorption kinetics was also studied to know the behavior and mechanism of adsorption and Pseudo 2nd order model was found to fit best. Adsorption equilibrium data were fitted reasonably well to Langmuir isotherm model. Regeneration study showed that the adsorbent could be used even after four cycles of operation.