Development of a bio-adsorbent medium to remove arsenic from water

摘要

The objective of this work was to study the removal of arsenic from water for human con-sumption by developing a bio-adsorbent using passion fruit, able to meet the maximum allowable limits of 0.025 mg L~(-1) established by Mexican NOM-127-SSA-1994. This was performed with synthetic water ([As] = 0.22 mg L~(-1)). The pectin was extracted using two methods, conventional acid extraction and alkali treatment with steam drag. After the pectin was extracted and characterized, experiments were performed to obtain adsorption kinetics and isotherms. The results showed adsorption kinetics of pseudo-second order with a rate constant of adsorption, k_(ad), of 2.107 g mg~(-1) min~(-1) for the acidic pectin and of 0.550 g mg~(-1) min~(-1) for the alkaline pectin. With regard to adsorption isotherms, the experimental data fitted thei Freundlich model, the KF being 2.08 for acidic pectin and 2.032 for alkaline pectin. Arsenic removal per-centages were 91% for acidic pectin and 81% for alkaline pectin.