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The feasibility of zinc oxide-catalyzed esterification of natural phytosterols with oleic acid was investigated well by a chemical process. The influences of various reaction parameters were evaluated. Basic solid zinc oxide is the most desirable catalyst due to its high selectivity (more than 90%), reusability, activity and less corrosivity, whereas sterol selectivity with other catalysts, such as H 2 SO 4 , NaHSO 4 and NaOMe, did not exceed 80%. Further results showed that during zinc oxide-catalyzed synthesis, the nature of the acyl donor was of paramount importance with direct esterification with fatty acids, which gives better results with higher conversion rate selectivity and more mild reaction conditions than transesterification with methyl esters. The substrate molar ratio of 2:1 (oleic acid/phytosterol) was optimal. Other parameters such as optimal catalyst load (0.5%) and temperature (170°C) showed a maximum production of steryl esters close to 98% after 8 h. It was also found that the amount of trans fatty acid formed in esterification was low, and the trans fatty acid content (%) in the phytosterol oleate ester fraction (3.26%) was much lower than that in free oleic oil (7.35%), which suggested that fatty acids in esters were more stable than free fatty acids regarding the combination with sterol. Immobilized ZnO could be a promising catalyst for replacing homogeneous and corrosive catalysts for esterification reactions of sterol.

A novel germanate |C(6)N(2)H(18)|(30)[Ge(9)O(18)X(4)](6)[Ge(7)O(14)X(3)](4)[Ge(7)O(14.42)X(2.58)](8)[GeX(2)](1.73) (X = OH, F) with 30-ring channels built from Ge(7)O(14)X(3) (Ge(7)) and Ge(9)O(18)X(4) (Ge(9)) clusters was obtained under solvothermal conditions. It has a mesoporous pore of 13.0 x 21.4 A(2), which represents the largest pore ring found in crystalline open-framework materials. The framework can be described as a 3-D net structure and viewed as introducing Ge(7) and Ge(9) clusters into the 4,8-heterocoordinated csq net.

This review focuses on the recent progress in MOFs and MOF-based materials as superior adsorbents for the efficient removal of uranium from aqueous solutions.