Synthesis and characterizations of nZVI-AC composites from coconut shells and its application for the adsorption of Pb(II) and Cr(VI) ions

Abstract

The nanotechnology development has spread not only in developed country but also in developing country such as Indonesia. This technology can be used in the management of sustainable and environment friendly of soil water resources. The nanoparticle which has particle size in the magnitude of nanometer exhibit a great potent in the treatment of water, wastes and pollution. Nano zero valent iron (nZVI) although is a promising material for such application, suffer from drawback of easily forms aggregate which decrease its mobility and reactivity towards degrading contaminant. To overcome this disadvantage property, synthesis of composite containing nZVI and activated carbon from coconut shell was conducted. Among supporting materials which added to improve stability, reactivity and mobility of nZVI, activated carbon is the most feasible choice due to its high adsorption capacity, large surface area, porous structure and abundantly available. Composite of nZVI and activated carbon is expected to possess combined property i.e. high adsorption capacity and the ability of nZVI to degrade contaminant. Preparation was conducted via sulphate method using NaBH4 reductor and FeSO4 as Fe2+ source. The ratio of nZVI and activated carbon was made by 1:1, 1:2 and 1:3. Particle size of the composite was reduced to 200 mesh and shows surface area of 398.721 m2/g. Characterization methods was carried out by using gas sorption analyser, XRD, SEM/EDS and FTIR. The composite made with 1:3 ratio was used to adsorb Pb(II) and Cr(VI). Characterization result shows that nZVI-activated carbon was formed as confirm by XRD and SEM/EDS. The reduction percentage against Pb(II) and Cr(VI) are 99.7% and 99.6% and the adsorption capacity according to these metal ions are 124.6 mg/g and 124.55 mg/g respectively.