Document Type: Regular Article
Department of Chemistry, G M R Institute of Technology, Rajam, Affiliated to JNTUK-Kakinada, 532127, A.P, India
Department of Chemistry, Andhra Polytechnic, Kakinada 533003, A.P, India
In this research paper, chemically activated Thuja Occidentalis leaves carbon (CATLC) is used as an adsorbent for the removal of calcium (Ca2+) ion from aqueous solution. CATLC is prepared and characterized by FTIR, SEM and EDX. The impact of pH, adsorbent dosage, contact period and initial concentration of Ca2+ on the adsorption performance of CATLC for Ca2+ removal are examined by batch studies. The results disclose that CATLC has a high potential to adsorb Ca2+ (91% removal) at pH 7.00. To know the equilibrium behaviour of Ca2+ adsorption, Freundlich and Langmuir models are investigated, and the data discloses that Langmuir model (maximum adsorption capacity ‘Qm’ obtained is of 51.28mg/g and R2= 0.9953) fits better than Freundlich model(R2 =0.8723). The Kinetic studies indicate that pseudo-second-order(R2= 0.9909) is the best fit rather than pseudo-first order, intra particle and Elovich models and chemisorptions are the rate-limiting steps for the Ca2+ adsorption using CATLC adsorbent. Regeneration studies showed that CATLC can be regenerated easily and reused for several adsorption cycles, with sodium chloride solution as a regenerating agent. The application of CATLC adsorbent is useful to reduce the hardness concentration in groundwater samples to meet the allowable limit according to WHO-2011 standards.