Author(s)

Basma G. Alhogbi^*, Zarifah F. Al-Enazi

Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, KSA.

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 q_m 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.

Coffee Husk Adsorbent, Zn²⁺ and Ni²⁺ Ions, Kinetic and Isotherm Models, Polluted Water

Alhogbi, B. and Al-Enazi, Z. (2018) Retention Profile of Zn²⁺ and Ni²⁺ Ions from Wastewater onto Coffee Husk: Kinetics and Thermodynamic Study. Journal of Encapsulation and Adsorption Sciences, 8, 1-17. doi: 10.4236/jeas.2018.81001.