Synthesis of silica nanoparticles from incinerated coconut shell for heavy metal removal

Abstract

Cocos nucifera which is commonly known as coconut has a layer called as endocarp (coconut shell) believed to have high content of silicon which is capable to produce value-added silica nanoparticles (SiNPs). Since SiNPs is good absorbent, in this case it is used in the removal of heavy metals due to the fact that it is hazardous even at low concentrations. SiNPs is synthesis using sol-gel method and it is in white powder form with 25.6% of recovery. It has irregular spherical shapes, smooth faced and finely clumped. Whereas, the extracted data of EDX and XPS results in prominent peaks of Silicone (Si) and Oxygen (O) element which verifies the production of SiNPs. The particle size of SiNPs are 1283.4 nm diameter and it is believed to have amorphous nature based on SAED and XRD result. FTIR analysis resulted the presents of Si-O-Si and stretch of Si-O bonds at the peak of 1097.06cm -1 and 797.0cm-1 respectively. Nevertheless, TGA analysis results in three stages of mass loss which is within range (33°C - 78°C), (78°C - 180°C) and (180°C - 600°C). In term of application this thesis focus on the removal of heavy metal in copper (II) sulphate solution via adsorption test and adsorption spectrum based on UV-visibility analysis. Despite, the percentage of removal adsorbent depends on the percentage of heavy metal concentration. Lastly, when the concentration SiNPs increase, the percentage of adsorbent removal increase. In a nutshell, all the objective been achieved in this project.