Efficient Removal of As(III) and As(V) from Contaminated Water Using Novel Synthesized Porous Geopolymer

Abstract

Millions of people all over the globe are highly affected by arsenic toxicity. The aim of current study was to synthesis of porous geopolymer for effective arsenic As(III) and As (V) sequestration from aqueous solution. In addition to that morphological and chemical analysis of adsorbent was conducted by Scanning Electron Microscopy (SEM), Energy Dispersion X-Ray Spectroscopy (EDX) and Fourier Transform Infrared radiations (FTIR) and BET. FTIR results reveled the formation of Si–O–Si and Si–O–Al bonds which confirmed the construction of geopolymer. SEM images represent that adsorbent has a regular, spherical and interconnected porous structure with greater specific surface area and porosity. The best removal efficiency of As(III) was 62 % at optimized operating conditions of pH 5-6, adsorbent dose 1 gm and initial concentration of pollutant 50 ppb, however As(V) removal efficiency was 94 % at optimized operating conditions of pH 7-9, adsorbent dose 1 gm and initial concentration of pollutant 50 ppb. The experimental results was validated by renowned Freundlich adsorption isotherm model and peuso second order kinetic model. The correlation coefficient (R2) value obtained was 0.968 and 0.949 for As(iii) and As(V) Freundlich model respectively. While R2 was 0.98 and 0.99 for pseudo second order kinetic model. It was determined from R2 that experimental results fitted well to Freundlich adsoprtion isotherm model and pseudo second order kinetic model. The results shows that adsorption capacity for As(iii) and As(v) is greater than adsorption capacity obtained by other researchers using various adsorbents.

Keywords

• water treatment
• adsorbent
• arsenic
• porous geopolymer