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In this study, the clam shell, a waste biomaterial, was modified with phosphoric acid to improve the adsorption amount of Orange II dye. The effects of initial concentration, contact time, and temperature on the adsorption were studied. The equilibrium adsorption data of Orange II on the phosphoric acid-modified clam shell powder (PCSP) were adequately represented by Langmuir isotherm with an adsorption capacity of 1,017.13 mg/g, which is higher than that obtained using raw clam shell powder. Adsorption kinetics followed the pseudosecond-order rate expression. Thermodynamic parameters show that the process is exothermal, feasible, and spontaneous. The effect of temperature inferred that the type of adsorption in the study is a physical adsorption. Therefore, PCSP is an efficient and economical adsorbent for dye removal.

The equilibrium relation of solute and solvent and the effect of organic carbon (OC) content on the sorption were utilized to study the sorption of acenaphthene, β-naphthol, phenol and naphthalene to organobentonite at various amounts and kinds surfactants (i.e., cetyltrimethyl ammonium bromide (CTMAB), dodecyltrimethyl ammonium bromide (DTMAB) and octadecyltrimethyl ammonium bromide (OTMAB)). The prediction model for contaminants removal was established by the quantitative relationship between K ow of organic contaminant and the exchange capacity of organic bentonite with different surfactants. The results showed that the prediction model for the sorption of compounds with high K ow (e.g., phenanthrene and naphthalene) got a better correlation and a smaller prediction deviation; conversely, a larger prediction deviation was got for the sorption of compounds with a low K ow (e.g., nitrobenzene).