Wang Shaobin, Zhu Z H
Department of Chemical Engineering, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia.
J Colloid Interface Sci. 2007 Nov 1;315(1):41-6. doi: 10.1016/j.jcis.2007.06.034. Epub 2007 Jun 23.
Fly ash is solid waste from combustion process, containing oxide minerals and unburned carbon. In this investigation, fly ash has been separated into metal oxide mineral section and unburned carbon. The fly ash with different contents of unburned carbon was employed for humic acid adsorption to investigate the influence of unburned carbon on adsorption. It is found that metal oxides and unburned carbon in fly ash exhibit significant difference in humic acid adsorption. The unburned carbon plays the major role in adsorption. Higher content of unburned carbon in fly ash results in higher surface area and thus higher humic acid adsorption. Fly ash and unburned carbon exhibit adsorption capacity of humic acid of 11 and 72 mg/g, respectively, at 30 degrees C, pH 7. Humic acid adsorption is also affected by ion strength, pH, and temperature. The thermodynamic calculations indicate that the adsorption is endothermic nature with DeltaH(0) and DeltaS(0) as 5.79 kJ/mol and 16.0 J/K mol, respectively.
粉煤灰是燃烧过程产生的固体废物，含有氧化物矿物和未燃尽碳。在本研究中，粉煤灰已被分离为金属氧化物矿物部分和未燃尽碳。使用具有不同未燃尽碳含量的粉煤灰进行腐殖酸吸附，以研究未燃尽碳对吸附的影响。研究发现，粉煤灰中的金属氧化物和未燃尽碳在腐殖酸吸附方面表现出显著差异。未燃尽碳在吸附中起主要作用。粉煤灰中未燃尽碳含量越高，表面积越大，因此腐殖酸吸附量越高。在30℃、pH值为7时，粉煤灰和未燃尽碳对腐殖酸的吸附容量分别为11和72mg/g。腐殖酸吸附还受离子强度、pH值和温度的影响。热力学计算表明，吸附是吸热性质的，ΔH(0)和ΔS(0)分别为5.79kJ/mol和16.0J/K mol。
