Preparation, characterization and application of activated carbon from agricultural solid wastes / Norli Umar

Norli , Umar (2022) Preparation, characterization and application of activated carbon from agricultural solid wastes / Norli Umar. Masters thesis, Universiti Malaya.

	PDF (The Candidate's Agreement) Restricted to Repository staff only Download (272Kb)
	PDF (Thesis M.A) Download (4Mb)

Abstract

The purpose of this study was to prepare activated carbon (AC) from palm kernel shells (PKS) and coconut shells (CS) as soot adsorbents. The proximate, ultimate, and lignocellulosic background study was conducted to determine the composition of the starting material. Thermogravimetric analysis (TGA) was used to verify the lignocellulosic content and thermal stability of the biomass. Following this, an optimization study was conducted to produce AC with the desired properties. Fourier Transform Infra-red (FTIR) analysis was conducted as validation of the optimization study. Carbonization was followed by chemical activation (H3PO4, KOH and ZnCl2) and finally microwave radiation treatment. The percentage yield was calculated to determine the efficiency of AC production. The surface area was determined using the Brunauer-Emmett-Teller (BET) method, and the surface acidity and basicity were determined using Boehm titration. Field Emission Scanning Electron Microscope (FESEM) was used to gain insight into the morphology of the AC. Energy Dispersive X – Ray analysis (EDX) was conducted to identify soot presence on the AC surface. The composition analysis reveals that despite the starting materials being from different plant species, both PKS and CS have similar chemical compositions except ash content. In this work, the ash content is found to be 2.16% and 0.24% for PKS and CS, respectively. In addition, PKS primarily comprised of lignin (40.7%) while CS mainly comprised of hemicellulose (38.9%). The optimal carbonization temperature used for preparation of biochar was 650°C and 600°C for PKS and CS, respectively. Each biochar or carbonized biomass was activated at a 1:1 w/w ratio of carbonized biomass and activating agent for 30 minutes at room temperature followed by 4 minutes of microwave radiation. After the optimized method was implemented, CS and PKS activated with ZnCl2 and microwave radiation (MZCS and MZPKS) has the most suitable characteristic to be applied as a soot adsorbent. This is due to the BET surface area collected being the highest at 391.26 m2/g for MZCS and 367.12 m2/g for MZPKS. In addition, the percentage yield of both AC is acceptable and the morphology shown in FESEM images showed the most uniform pores. Through Boehm titration, it was discovered that the MZCS and MZPKS surface was predominantly acidic. After MZCS and MZPKS were exposed to soot emitted from paddy straw burning, MZCS shows the most visible physical adsorption and an even distribution of soot on the surface and within the pores. The MZCS maximum capacity was 30 minutes for approximately 23 g of paddy straw burning using 0.1 g of AC. Economic feasibility studies have been conducted and it has been determined that the laboratory scale price of AC is 4.78 USD / kg.

Actions (For repository staff only : Login required)