TITLE:
Retention Profile of Zn2+ and Ni2+ Ions from Wastewater onto Coffee Husk: Kinetics and Thermodynamic Study
AUTHORS:
Basma G. Alhogbi, Zarifah F. Al-Enazi
KEYWORDS:
Coffee Husk Adsorbent, Zn2+ and Ni2+ Ions, Kinetic and Isotherm Models, Polluted Water
JOURNAL NAME:
Journal of Encapsulation and Adsorption Sciences,
Vol.8 No.1,
March
26,
2018
ABSTRACT: In this work, Coffee husk (CH) was used as a solid phase extractor (SPE) for removal and/or minimization of Zn2+ and Ni2+ ions in aqueous media. XRD, FESEM and FTIR analysis of the SPE were performed for surface morphology and function groups characterisation. Batch mode adsorption studies were performed by varying the operational parameters such as adsorbent dose, solution pH, initial analyte concentration and contact time. The equilibrium data of both analytes was found a better fit with the Langmuir and Freundlich isotherm models. The qm of Langmuir for Zn2+ and Ni2+ ions were 12.987 and 11.11 mg/g, respectively. The adsorption capacities of the CH adsorbent towards Zn2+ and Ni2+ resulted of 12.53 and 10.33 mg/g, respectively. In addition, the kinetic data of Zn2+ and Ni2+ ions uptake revealed that the present system fitted well with pseudo-second-order kinetic model (R2 > 0.99). Thermodynamic studies showed that the retention step was exothermic, and spontaneous in nature. The results indicated that the coffee husk provides an effective and economical approach in highly reducing or almost eradication of both metals Zn2+ and Ni2+ from the aqueous solution.