The potential of recovering phytosterols from fatty acid methyl esters by an adsorption‐desorption process is demonstrated using a strong‐acid ion‐exchange styrene‐divinylbenzene resin (SA‐R) as an adsorbent and ethanol as a desorbent. Since the operating cost of the overall process significantly depends on the efficiency of SA‐R in the adsorption step, the behavior of SA‐R in sterol adsorption is investigated in detail using a model solution of stigmasterol in n‐heptane. The results indicate that stigmasterol was associatively and exothermically adsorbed on SA‐R. Based on the experimental results, a simple pseudo‐second‐order model and a modified Langmuir isotherm with their parameters, which well predicted kinetics and adsorption capacity of SA‐R, are proposed.

Effects of activation variables on performance of the obtained activated carbon (AC) were investigated for removal of tetracycline hydrochloride (TCH).  Pyrolytic char derived from waste tire was chemically activated via two-step of KOH impregnation following by thermal treatment.  According to regression analysis and fitting with second-degree polynomial equation, empirical models were developed to correlate performance of AC in TCH adsorption (percentage removal and adsorption capacity at equilibrium) with three activation variables: impregnation ratio (IR), activation temperature (T) and holding time of thermal treatment (t).  The analysis of variance indicated that only T, T2 and IR2 were significant to the prediction of both percentage removal and adsorption capacity.  According to the developed models, it is suggested that the pyrolytic char should be activated at IR = 6, T = 750 °C and t = 2 h to obtain the highest efficiency of TCH removal in the tested range of activation condition.

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