Rate of Controlled-Release Urea Pervasion through Membrane Determined by Ultraviolet Spectrophotometry
ZUO Xiu-jin1, 2, 3, WANG Zhen-xin2, DAI Xiao-min2, ZHOU Yi2, MA Xiao-jun1
1. Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dilian 116013, China 2. Dalian University, Institute of Environment and Chemical Engineering, Dilian 116622, China 3. Graduate School of Chinese Academy of Sciences, Beijing 100089, China
Abstract：Application of controlled-release nitrogenous fertilizers can improve the efficiency of fertilizers and reduce the environmental pollution. Controlled-release urea (coated urea) is one of the controlled-release nitrogenous fertilizers developed quickly in the recent years. The rate of controlled-release urea pervasion through membrane is the most important index of the capacity of controlled release. There is a maximum absorption at λ=426 nm with complex in acidic solution, using p-dimethylaminozenzaldehyde as color reagent, and the absorbance exhibits a linear reponses to the urea concentration over the range of 7.5-210 μg·mL-1. The method for determining the rate of controlled-release urea pervasion through membrane was realized through determining the content of urea in the liquor, the recovery efficiency of the method is 96.1%-103.9%.
