Hydrothermal Synthesis, Characterisation and Adsorption Testing of MoS2-Zeolite for the Removal of Lead in an Aqueous Solution

Abstract

The shortage of water can be worsened by the pollution of limited water resources by industrial activities such as mining which contribute to significant level of toxic heavy metals in the environments. Heavy metals such as lead could negatively affect the health of consumers ingesting contaminated water and must therefore be removed from existing water sources to ensure that these sources can be used effectively and safely. In this study the potential of zeolite (clinoptilolite) and molybdenum sulfide as effective adsorbents and lead-selective adsorbent, respectively was considered for the hydrothermal synthesis of MoS2-Zeolite composite for effective removal of lead from aqueous solution. The synthesized composite and the parent compounds were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transformed infrared spectroscopy (FTIR). The results confirmed the properties of the adsorbents as well the successful synthesis of the composite. The adsorbents were used for the removal lead from solution while assessing the effect of adsorbent dosage and initial concentration of lead on the adsorption performance. It was found that clinoptilolite, MoS2 and MoS2-zeolite exhibited adsorption capacities of 3.45, 4.1 and 1.2 mg/g, respectively; indicating that MoS2 was the superior adsorbent. This implies that for metal contaminated solutions, MoS2 will be the ideal adsorbent for the removal of lead. Keywords— Water pollution, lead, adsorbents, zeolite, molybdenum sulfide, adsorption kinetics Manuscript received October 03, 2018. This work was supported in part by the North West University department of Chemical Engineering. E. Fosso-Kankeu is with the Water Pollution Monitoring and Remediation Initiatives Research Group in the School of Chemical and Minerals Engineering of the North West University, South Africa. F. Waanders is with the Water Pollution Monitoring and Remediation Initiatives Research Group in the School of Chemical and Minerals Engineering of the North West University, South Africa. Martin J. Spiro is with the Water Pollution Monitoring and Remediation Initiatives Research Group in the School of Chemical and Minerals Engineering of the North West University, South Africa. Nico Lemmer is with the Water Pollution Monitoring and Remediation Initiatives Research Group in the School of Chemical and Minerals Engineering of the North West University, South Africa. Neeraj Kumar is with the DST-CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, Pretoria 0001, South Africa. Suprakas S. Ray is with the DST-CSIR National Centre for Nanostructured Materials, Council for Scientific and Industrial Research, Pretoria 0001, South Africa.