Abstract
The use of biochar as an adsorbent for wastewater treatment purposes has been hindered due to its lower surface area compared to activated carbon. Current research on increasing surface functional groups on biochar surfaces to improve its adsorption performance suggests using high chemical concentration and long period of modification. This study solves these problems by focusing on improving surface functionalities of biochar via the hydrothermal functionalization process. Oil palm empty fruit bunch biochar was functionalized using autoclave with nitric acid as the functionalization agent. Functionalized biochar properties such as Brunauer–Emmett–Teller (BET) surface area and surface functional groups were analyzed and compared with untreated biochar. Fourier Transform Infrared (FTIR) spectroscopic analysis shows a significant increase in absorption by oxygen functional groups and is corroborated with energy dispersive X-ray (EDX) analysis. The process does not result in any major change in surface morphology and reduction in surface area value. Methylene blue (MB) adsorption test shows 7 times increase in adsorption performance. These results show that the simple hydrothermal functionalization process successfully functionalizes the biochar surface and improves its performance without affecting its surface area at lower concentration, and shorter time compared to previous studies. This result, with future large-scale experimentation using real-life equipment in palm oil mills, would provide a better technology that can be implemented in the industry.
Highlights
Production of carbon material from biomass for different purposes has gained interest in the sustainable technology development scene due to its simple and low-cost process
Fourier Transform Infrared (FTIR) Analysis The surface functional groups of EFB-BC and EFB-FBC was analyzed via FTIR to determine whether the process was able to functionalize the surface of the biochar
EFB-BC was successfully functionalized using nitric acid as an oxidizing agent, with autoclave as the accelerator for the process. The novelty of this process is that it effectively increases the amount of oxygen surface functional groups of biochar while using a significantly lower concentration of nitric acid and at a shorter treatment time compared to what is previously reported in the literature
Summary
Production of carbon material (biochar) from biomass for different purposes has gained interest in the sustainable technology development scene due to its simple and low-cost process. A large amount of OPEFB can be processed at once as reported by Idris et al, with a successful self-sustaining carbonization process, which can be upscaled to 3 tons per run [15,16]. These show the feasibility of OPEFB as biochar feedstock and with an increase in production scale, the cost can be driven down due to the economy of scale effect. While OPEFB biochar itself has a high gross calorific value (GCV) and can be used as fuel, the value of OPEFB biochar can be improved if it can be used as an adsorbent in wastewater treatment application
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