Study of adsorption capacity on textile dyes and heavy metal (Pb2+) using modified natural zeolite

Abstract

Water pollution by textile wastes is increasing every day. About 99% of textile dyes applied in the industry are classified as synthetic dyes which participate in carrying the remaining heavy metal lead (Pb2+) from the production process. To eclipse this problem, an effective but still economical purification process is needed so that it is easy to apply in the industry. A method that fulfills all the aforementioned requirements is the adsorption process using natural zeolite. In this study, methylene blue (MB) solution and Pb(II)-Acetate solution were used as representative models of synthetic compound waste to be adsorbed using Gunung Kidul natural zeolite modified with 0,4 M HCl solution. Modified zeolite was then characterized using SAA (Surface area analyzer) using the BET method, while the remaining concentration of MB and Pb2+ from the adsorption process were determined using a UV-vis spectrophotometer. The effect of adsorption time (30”; 60”; and 90”) and adsorbent weight (5 g; 10 g; and 15 g in 100 mL sample solution) on the adsorption capacity was analyzed for optimum conditions using the FCCD (Face centered cube design) method using Minitab 19 software. The results showed that there was an increase in adsorption capacity along with the increase in adsorption time and the amount of zeolite used. The optimum conditions for the absorption of MB and Pb2+ occurred with the use of the adsorbent weight of 5 g and a contact time of 60” with a predicted zeolite capacity of 0,390816 mg/g zeolite for MB and 0,0953138 mg/g zeolite for Pb2+. Meanwhile, the surface area of natural zeolite has increased from 19,118 m2/g to 57,838 m2/g after the modification process. Keywords : Adsorption, natural zeolite, heavy metal, dealumination