胺型腰果酚醛树脂对Ag~+的吸附

制备了3种胺型腰果酚醛树脂(二乙撑三胺型腰果酚醛树脂(PCD)、己二胺型腰果酚醛树脂(PCE)、己二胺型腰果酚醛树脂(PCH)),采用XPS(X-射线光电子能谱仪)、EA(元素分析仪)、FTIR(傅利叶变换红外光谱分析仪)等手段研究了其结构特征,并考察了其对水溶液中Ag+的吸附行为和机理.结果表明,3种树脂对Ag+有较高的吸附量和吸附作用;在pH值为5.5的条件下,树脂对Ag+的吸附效果最佳;2h内吸附达到平衡;吸附行为均符合Lagergren准二级速率方程;树脂对Ag+的吸附均符合Langmuir等温吸附方程;吸附反应为自发吸热和熵增的过程;可溶性无机盐对树脂吸附Ag+的影响不大;推测其吸附机理是树脂上胺基、羟基与Ag+发生较强的配位作用和较弱的离子交换作用的化学吸附为主.吸附Ag+后的树脂可用硝酸脱附再生;树脂循环使用4次后,吸附率和脱附率仍大于90%.     

Structure and antioxidant activity of phenolic compounds isolated from the edible fruits and stem bark of Harpephyllum caffrum

Antioxidant activity in edible fruits is an important characteristic in the choice of fruits for human consumption, and has profound influence on nutrition and health. Two pharmacologically active triterpenoids, β-sitosterol and lupeol, and the powerful flavan-3-ol antioxidant, (+)-catechin, were isolated from the edible fruits of Harpephyllum caffrum while a mixture of cardanols, an alkyl p-coumaric acid ester, and (+)-catechin were isolated from the stem bark. This is the first report of these compounds being isolated from this plant. The antioxidant capacity of (+)-catechin was higher than the other isolated compounds as well as the known antioxidant, ascorbic acid.