为控制海岸风沙侵蚀灾害、探索可行高效的海岸防风固沙新技术,基于酶诱导碳酸钙沉淀(EICP)原理开发以浓缩海水为可溶性钙盐溶液、以废弃豆皮为脲酶源的EICP固沙技术,开展了固化砂土风蚀试验,研究分析了脲酶活性、反应液喷洒量、处理次数、固化时间以及海盐浓度对固化效果的影响.研究发现,大豆种皮脲酶的活性在10～65℃范围内随温度升高而增加,随豆皮用量增大而增加,但脲酶提取时的离心时间和离心转速对脲酶活性无明显影响.采用大豆种皮与海水作为原料的EICP固化试样,能达到防风固砂的效果.当脲酶活性固定时,增加处理次数、喷洒量和固化时间可提高表面贯入强度,但达到一定阈值后效果逐渐减弱.在反应液总量相同的情况下,分批多次处理的碳酸盐沉淀生成率更高;起动风速较大,抗风蚀效果较好,相比之下,一次集中处理的效果较差.为获得较好的抗风蚀效果,浓缩海水的浓度不应低于0.6 mmol/L,固化时间不超过12 h.
Experimental Study on Wind Erosion Resistance of Sandy Soil Stabilized by Enzyme-Induced Carbonate Precipitation with Urease from Soybean Skin
To control coastal wind erosion and explore feasible and efficient new technologies for coast-al windbreaks and sand fixation,this study developed the Enzyme-Induced Calcium Carbonate Precipi-tation(EICP)sand stabilization technique.The technique used concentrated seawater as a soluble calci-um salt solution and discarded soybean husks as a source of enzyme urease.Wind erosion tests on sta-bilized sand were conducted,and the effects of urease activity,spray volume of the reaction fluid,number of treatments,curing time,and seawater salinity on stabilization efficacy were analyzed.Re-sults indicated that the activity of urease from soybean skin increased with rising temperatures within the range of 10-65°C and also increased with the amount of soybean skin used.Centrifugation time and speed during urease extraction had no significant effect on urease activity.Samples solidified with soy-bean skin and seawater demonstrated effective windbreak and sand fixation.When urease activity was fixed,an increased number of treatments,spray volume,and curing time enhanced surface penetra-tion strength,though the effect gradually diminished beyond a certain threshold.With the same total volume of reaction fluid,multiple incremental treatments resulted in higher carbonate precipitation rates,higher threshold wind velocities,and better wind erosion resistance compared to a single cen-tralized treatment.For optimal wind-erosion resistance,the concentration of concentrated seawater should not be lower than 0.6 mmol/L,and the curing time should not exceed 12 hours.
万方数据
维普
