Heat Carbonization and ZnCl2 Functionalization of Date Stone as an Adsorbent: Optimization of Material Fabrication Parameters and Adsorption Studies

Abstract

The scientific community gave a lot attention to prepare adsorbents from different natural agriculture-based materials to be used alternative to commercial activated carbon. However, less studies on the optimization of fabrication parameters to obtain activated carbon with highly surface area and adsorption capacity. Herein, we report the synthesis conditions optimization of adsorbent based on date stone and modified with ZnCl2. To obtain a highly adsorption ability of the materials, three systematic parameters were evaluated such as the activation temperature, activation time and the functionalization ratio by ZnCl2. The optimization study showed that the best factors to fabricate an adsorbent from date stone are 700°C, 120 min and 2.0 (g/g), wherein, the specific surface area was found to be 1036 m2/g. While, the iodine and phenol numbers were 928.5 mg/g and 2.1 mmol/g, respectively. To further understand the effect of synthesis parameters, the raw and the as-synthesized activated carbon were characterized via Fourier transmission infrared spectroscopy (FT-IR), X-ray diffraction (XRD), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). Batch sorption tests to remove MB from water showed a maximum adsorption capacity of 384.6 mg/g using the prepared activated carbon at pH 6 and room temperature (25±2 °C). It was found also that the kinetic adsorption data obeyed the pseudo-second order and, both external diffusion and intra-particle diffusion control the adsorption. Based on the obtained results, the optimization of synthesis conditions through experimental and mobilization studies may help the transfer of technology in terms of agriculture-based materials valorisation towards the environmental remediation.