CAJ | 학술논문

针对荒漠化地区生态恢复中沙土有效水分涵养难的问题，采用十二烷基苯磺酸钠（linear alklybezene sulfonates，LAS）与黏土复合制备土基改性材料。研究了材料在模拟沙漠气候条件下的保水性能，并测试材料老化后抗压强度损失率和质量损失率以及其保水性能的变化。采用扫描电子显微镜、傅里叶红外光谱分析、X 射线衍射分析、热重分析对材料保水机理进行研究。结果表明，土基改性材料保水性能良好，改性后黏土的片层结构和化学成分没有明显变化，通过LAS亲水端与黏土中结合水的相互作用，将松散的黏土胶结起来，LAS中憎水端相互连接形成憎水网络，从而在地表形成透气保水的固结层来有效降低水分蒸发。模拟沙漠气候条件下的植草试验表明当 LAS 和黏土的质量比为2∶1时，土基改性材料保水透气性能较佳，草籽发芽率从对照组的8%提高到43%。研究结果为制备新型土基固沙植草材料提供参考。
침대황막화지구생태회복중사토유효수분함양난적문제，채용십이완기분광산납（linear alklybezene sulfonates，LAS）여점토복합제비토기개성재료。연구료재료재모의사막기후조건하적보수성능，병측시재료노화후항압강도손실솔화질량손실솔이급기보수성능적변화。채용소묘전자현미경、부리협홍외광보분석、X 사선연사분석、열중분석대재료보수궤리진행연구。결과표명，토기개성재료보수성능량호，개성후점토적편층결구화화학성분몰유명현변화，통과LAS친수단여점토중결합수적상호작용，장송산적점토효결기래，LAS중증수단상호련접형성증수망락，종이재지표형성투기보수적고결층래유효강저수분증발。모의사막기후조건하적식초시험표명당 LAS 화점토적질량비위2∶1시，토기개성재료보수투기성능교가，초자발아솔종대조조적8%제고도43%。연구결과위제비신형토기고사식초재료제공삼고。
Desertification is one of the most serious environment problems in the world. Three methods commonly used in desertification control are engineering, chemical and biological sand fixation. Aiming at available water conservation in desertification ecological restoration, the clay-based modified materials were prepared by clay and sodium dodecyl benzene sulphonate (LAS) composite. LAS (2, 4, 6 and 8 g) was individually dissolved into 15 g distilled water while strong stirring for 10 minutes. Then, 3 g bentonite was slowly added into the solutions under strong stirring. The slurry was sprinkled onto sand with a relative humidity of 40%. The samples were regarded as L1, L2, L3 and L4, respectively according to the different contents of LAS (2, 4, 6 and 8 g), and the original clay L was as control group. The water retention property was studied in simulated desertification climate and the materials were analyzed and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and thermal gravity analysis (TGA). The materials were placed at 30 cm blow the 500 W ultraviolet (UV) carbon arc lamp to test the resistance to aging. The results showed that the water content of the control group fell sharply to zero just in 3 days. The falling rates of the water content for all the modified materials slowed down, and the water retention property was improved with increasing LAS content. L4 had the best performance for moisture content of 3.2% on the tenth day. It was because the clay particles had been cemented into large particles by LAS and the hydrophobic ends of LAS were connected to form a hydrophobic network that can inhibit water evaporation. As such, samples with high LAS content had better water retention ability. The aging results showed that the compression strength were all higher than 4.25 MPa. Samples with high LAS content had higher strength and the compression strength of L4 was 6.35 MPa. The compression strength and mass lost was small after aging and highest in samples with high LAS content. After 300 hours aging, the lost of L4 was highest with the strength loss rate of 8.7% and mass loss of 1.7%. It was because the photolysis rate of LAS in solid-state was very low and its decomposition temperature was above 450℃. So the materials had good performance of resistance to aging. The SEM images showed that the original clay particles were small and loosely arranged. There were abundant channels of different pore size to transport water. The clay particles in the modified materials were cemented by LAS so that some water conducting channels were cut off. At the same time, the interaction of hydrophobic ends of LAS made more clay pores changing from hydrophilic to hydrophobic state. Then it was more difficult for water to rise and so the water retention property was enhanced. The FTIR figure showed that the infrared absorption characteristic peaks of original clay also existed in the modified clay, which indicated that the phase composition of clay did not change. The XRD figure showed that d001interlamellar crystal spacing was 1.40643 nm for original clay, and 1.42420 nm for the modified clay. And there was almost no change in the interlamellar crystal spacing, which indicated that the modification didn’t change the layered microstructure. The TG and DSC curves showed that the original clay kept losing water over temperature and most of the free water and interlayer adsorbed water escaped at and below 200℃. By comparison, there was almost no moistureloss of modified clay below 200℃. It was because the interaction between hydrophilic ends of LAS and the free water and adsorbed water made the water more stable. Grass-planting experiment showed that reasonable mass ratio of LAS and clay was 2:1. The materials not only had good water retention property but also maintained sound air permeability so the germination rate of grass seed significantly increased from 8% to 43%. After that, more LAS would block a part of the clay pores, which would influence the air permeability and thereby decrease the germination rate.