不同因素对牡蛎壳吸附尿素的性能及缓释性的影响

采用紫外可见分光光度计法,在吸附温度、吸附时间、pH等不同参数条件下测定了牡蛎壳粉对尿素的吸附率及吸附后的缓释度。单因素试验结果表明：牡蛎壳粉对尿素吸附性较好的最佳吸附参数是,吸附温度为45℃、吸附时间为3 h、pH为8.5、牡蛎壳粉活化温度为700℃、活化时间为2 h;在最佳吸附参数条件下,牡蛎壳粉对尿素的最大吸附量为35.7 g/kg;牡蛎壳粉吸附尿素后其缓释性较好,25℃下静水中28 d内缓释度小于80%,尿素释放期约为35 d,释放期内日平均释放率较平稳。

Absorption and releasing of urea by oyster shells

Absorption rate of urea and slow-releasing rate by oyster shells were determined under different water temperature, and absorption period by UV spectrophotometer. Single factor experiment revealed that the absorption of urea was very high by the oyster shells, the maximal absorption （35.7 g/kg） was found under the conditions of urea consumption of 20 g, a temperature of 45℃, period of 3 h, pH 8.5, and oyster shell activation at temperature of 700 ℃, and period of 2 h. Slow-releasing of urea absorbed by oyster shells was good. In 25℃ calm water, the slow-releasing degree was less than 80% within 28 days with urea releasing period of about 35 days, and daily average stable releasing rate in the releasing period.