Release Performance Of Cryogel Beads And Application In Coastal Wetlands Bioremediation Engineering Research

Bioremediation is one of the three major means to reduce pollution.Due to its good effect,the adventage of no secondary pollution and high social value,bioremediation methods is getting more and more practical application in the environmental pollution aspect.Fortified nutrition method which enhances effect by dropping nutrient is one of the main form of bioremediation as its good remediation effect and convenient for operation,but there is several research of nutrition agent with slow release.This paper explores preparation,release performance of cryogel beads and their effcient application in coastal wetlands bioremediation engineering.We prepared six kinds of cryogel beads of the phosphate-loaded type with film(AP-A),phosphate-loaded type without film(AP-B),urea-loaded type with film(AN-A),urea-loaded type without film(AN-B),balance type with film(APN-A)and balance type without film(APN-B),using low temperature freezing crystallization method.Furthermore,the basic properties of cryogel beads were researched.Cryogel beads have pore structure and their porosities vary from 7.00% to 13.60%.The diameter distributions are narrow with size of 3.27-4.37 mm.The cumulative release performance of cryogel beads in short-term replace leaching type study shows that: the respective release quantity of total phosphorus is 14.24,8.31,10.79 and 6.82 mg/g for AP-A,AP-B,APN-A and APN-B,with release period in 112.5,50.5,75 and 35.5 days respectively.The respective release quantity of total urea of AN-A,AN-B,APN-A and APN-B is 178.53,93.44,19.48 and 3.83 mg/g,and the correspond release period is 2.5,1.5,1 and 1 day.Obviously,cryogel beads with film show higher release quantity than those without film.The research of the cumulative release performance of cryogel beads in long-term replace leaching type suggests that: the release quantity of total phosphorus is 15.21,11.33,11.46 and 6.83 mg/g for AP-A,AP-B,APN-A and APN-B respectively,with correspond release period of 80% amount of phosphorus in 210,126,112 and 42 days.The respective release quantity of total urea of AN-A,AN-B,APN-A and APN-B is 142.48,29.07,1.73 and 1.48 mg/g,and the correspond total release period is 5,5,3 and 3 days.Finally,we get that cryogel beads which contain phosphorus show long-term release features,and cryogel beads with film reflect more durable release performance than those without film.Six tons of cryogel beads were prepared and used in coastal wetlands bioremediation engineering.After construction,total nitrogen content is increased by 26.4% and the effective phosphorus content is increased by 52.3%,microbial content is increased by 25.7% to 53.8% in the soil of Jinzhou.Microbial content is increased by 55.6% to 66.8% in the soil of Xingcheng.Project practise suggests that application of cryogel beads can improve the efficiency of bioremediation,reflecting that the application of cryogel beads have engineering significance.