Han Guo,Yang Zhen,Yang Xiao-xue,Zhang Xiao-a,Jiang Sheng-ling,Lu Ya-fei
Carborane bisphenol novolacs ( 3 and 4 ) were synthesized in the presence of acid catalyst from carborane bisphenols ( 5 and 6 ) and formaldehyde. Further epoxidization of carborane bisphenol novolacs with epichlorohydrin gave carborane bisphenol epoxy novolacs ( 1 and 2 ). The molecular weight and epoxy value of obtained resins were determined using the molecular weight of their precursors. The epoxy values of 1 and 2 were 0.48 and 0.52 respectively, higher than the maximum theoretical epoxy value (0.45) of difunctional carborane bisphenol epoxy resins. FTIR and NMR were utilized to characterize 1 and 2 . The curing behaviors were also studied by DSC and the optimized curing conditions were obtained. TGA analysis indicated that carborane moiety could shield its adjacent organic structures against initial decomposition. On the other hand, B―H on carborane cage could react with oxygen to form a three-dimensional network linked by B―O―B and B―C bonds, which further blocked the movement of formed radicals and thus the degradation process was inhibited.
In this study, CMC–LDH beads were prepared and characterized using SEM, FTIR and TG analysis. The beads were applied for the removal of Cr(VI) from aqueous solution. The effects of adsorbent dosage, initial pH and initial concentration of Cr(VI) solution on Cr(VI) uptake were investigated in detail. Moreover, adsorption isotherms and adsorption kinetic models were employed to analyze the adsorption process, and a preliminary study of the reusability of the adsorbent was performed. The experimental results showed that the CMC–LDH beads could remove Cr(VI) from aqueous solution efficiently. When the initial concentration of the Cr(VI) solution was 100 mg L−1 and the adsorbent dosage was 12 g L−1, the removal efficiency of Cr(VI) reached 96.2%. After the CMC–LDH beads were reused 10 times, the removal efficiency of Cr(VI) still remained at 89.6%.