ASAM HUMAT TINJA KUDA SEBAGAI GREEN ADSORBEN PADA ADSORPSI LOGAM Pb(II) DAN Ni(II); HORSE FECES HUMIC ACID AS A GREEN ADSORBENT ON THE ADSORPTION OF Pb(II) AND Ni(II)

Rohmatullaili, Bambang Rusdiarso

2015 | Disertasi | FMIPA

Horse feces had been confirmed as a green source of humic acid, the extracted humic acid was then used as an adsorbent for Pb(II) and Ni(II) adsorption. Extraction of humic acid from horse feces was done according to IHSS (International Humic Substance Society) procedure in O2 atmosphere. Based on the extraction treatment, there were 4 types of extracted horse feces humic acid. Adsorption ability of that 4 extracted humic acid types was tested. Pure horse feces humic acid (pure HFHA) that has the highest content of total acidity, showed the most excellent adsorption ability. The amount percentage of pure horse feces humic acid was about 0.40%. The study of adsorption aspects were effect of pH, contact time, kinetics, capacity, adsorption energy, and competitive adsorption of Pb(II) and Ni(II) in pure HFHA. In the pH range lower than the neutral charge point of each metal, increasing pH caused percentage of adsorption increased, the optimum pH of Pb(II) adsorption was 5, and Ni(II) was 7. The adsorption rate constant of Ni(II), that was 0.071 g/mg minute, was faster than Pb(II), that was 0.024 g/mg minute, indicated that the optimum contact time of Ni(II) adsorption was faster than Pb(II). Adsorption of Pb(II) and Ni (II) in pure HFHA followed Langmuir adsorption isotherm, with adsorption capacity of Pb(II) was 100 mg/g and Ni(II) was 27.78 mg/g, and the amount of adsorption energy of both metals showed the chemisorption process. Pb (II) tend to win the competitive adsorption to Ni(II) because Pb(II) has smaller size of ion hydrate, it caused the rate of Pb(II) diffusion in the surface of humic acid faster than Ni(II).

Kata Kunci : humic acid; horse feces; competitive adsorption; Pb(II); Ni(II).