Adsorption of Mn2+ from aqueous solution using Fe and Mn oxide-coated sand.
The adsorption of Mn2+ onto immobilized Mn-oxide and Fe-oxide adsorbent such as manganese oxide-coated sandl (MOCS1), manganese oxide-coated sand2 (MOCS2), iron oxide-coated sand2 (IOCS2), and manganese and iron oxide-coated sand (MIOCS) was investigated. The effects of pH (5.5 to 8.0) and temperature (25 to 45 degrees C) on the equilibrium capacity were examined. Equilibrium studies showed that there is a good fit with both Freundlich and Langmuir isotherm, which indicates surface heterogeneity and monolayer adsorption of the adsorbents. Kinetic data showed high correlation with the pseudo second-order model, which signifies a chemisorption-controlled mechanism. The activation energies, activation parameters (deltaG, deltaH, deltaS), and thermodynamic parameters (deltaG0, deltaH0, deltaS0) confirmed that adsorption with MIOCS was endothermic and more spontaneous at higher temperature while an opposite trend was observed for the other adsorbents. Thermodynamic studies showed that adsorption involved formation of activated complex, where MOCS 1 and MIOCS follow a physical-chemical mechanism, while MOCS2 and IOCS2 follows purely chemical mechanism.
Institute of Hot Spring Industry, Chia Nan University of Pharmacy and Science, Taiwan, China. cckanev@mail.chna.edu.tw
Chi-Chuan
CC
Kan
Mannie C
MC
Aganon
Cybelle Morales
CM
Futalan
Maria Lourdes P
ML
Dalida
D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008345:Manganese / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D017895:Manganese Compounds; D010087:Oxides; D012996:Solutions; D014874:Water Pollutants, Chemical; D008345:Manganese; C027424:manganese oxide; D012822:Silicon Dioxide; D007501:Iron