Palm leaves based biochar: advanced material characterization and heavy metal adsorption study

The current report provides the synthesis and characterization of palm tree leaves biochar (PL-BC) prepared by simple thermal pyrolysis at 550 degrees C, which was then used for the elimination of lead and chromium from aqueous solution. An advanced material characterization was conducted by XPS, SEM, EDS, and FT-IR for the raw and spent PL-BC. Moreover, detailed surface chemical state analysis and identification of the chemical species was conducted by the XPS. The XPS surface analysis revealed high carbon content 78.5% while the BET surface area was 21.6 m(2)/g. The surface oxygen content was about 15.7% suggesting the abundance of oxygen functional groups onto the PL-BC. The adsorption results demonstrated that the removal of lead and chromium by PL-BC obeyed to Freundlich model, while kinetics data obeyed to pseudo-second order model. Furthermore, the Freundlich maximum adsorption uptakes for lead and chromium were 79.2 mg/g and 51.9 mg/g, respectively. The reusability studies demonstrated that more than 64% of the initial remediation efficiency of lead and chromium can be achieved after five adsorption/desorption cycles. Moreover, the PL-BC was able to reduce the lead and chromium content from injected actual brackish water of 1 mg/L to the international allowable limits of drinking water (<50 mu g/L). The remediation of lead and chromium by PL-BC was controlled by physical and chemical adsorption processes and dominated by complexation, precipitation, and ion exchange. These outcomes disclose the mechanism of lead and chromium removal by PL-BC and provide a sustainable solution of utilizing agriculture waste in water treatment.