Study of Mechanism of the W-OH Sand Fixation

Weimin Gao, Zhiren Wu, Zhishen Wu

Department of Urban and Civil Engineering, Ibaraki University, Hitachi, Japan.
Jiangsu ATK Environmental Engineering Design and Research Institute Co., Ltd., Wuxi, China.

DOI: 10.4236/jep.2012.39119                

Abstract

A novel hydrophilic polyurethane (abbreviated as W-OH) was developed and applied as a sustainable sand-fixing material. This paper on the chemical sand fixation mechanism of W-OH discusses the adhesive force between the W-OH solid and sand particles. The solidification mechanism was investigated and the solidifying time was tested. And then the thickness and porosity of the W-OH sand-fixing layer were investigated. By scanning electron microscopy (SEM), the microstructure of the W-OH sand-fixing layer was examined. The hardness and compressive stress of the sand-fixing specimens were studied at W-OH different concentrations. Finally, the resistance to wind erosion of the W-OH sand-fixing layer was investigated by a wind tunnel test. The results demonstrated that the W-OH aqueous solution had an excellent affinity for water on the surface of the sand particles, and the adhesive force between the W-OH solid and sand was primarily hydrogen bonding, covalent bonds and physical absorption, such as Van Der Waals forces. W-OH is a prepolymer of hydrophilic polyurethane containing groups of -NCO that can quickly react with water and other groups containing active H. The W-OH aqueous solution solidified in the range of 2 min to 15 min. The solidifying time decreased with increasing temperature and concentration. Before solidifying it had a good permeability of sand and the formed sand-fixing layer had a thickness of 8 - 35 mm and a porosity of 25% - 8% at a spraying concentration of 2 - 10 L/m². The hardness index of the sand-fixing layer was in the range of 21 mm to 28 mm and compressive stress was in the range from 0.21 MPa mm to 1.27 MPa, both of which increased linearly with W-OH concentration. Sand treated by over 3% W-OH concentrations showed excellent resistance to wind/sand erosion of more than 25 m/s.

Keywords

W-OH Sand Fixation; Adhesive Force; Porosity; Solidifying Time; Wind Tunnel Test

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	UNEP, “United Nations Convention to Combat Desertification,” UNEP, Nairobi, 1994, p. 35.
[2]	J. Jian, H. J. Li and X. A. Dai, “Research on Land Sandy Desertification Using Remote Sensing Taking Qinghai Lake Area as an Example,” Geo-Information Science, Vol. 8, No. 2, 2006, pp. 116-120.
[3]	L. L. Wang, Z. Y. Qin and N. S. Qin, “Climate Change and Its Impact on Desertification around Qinghai Lake,” Plateau Meteorology, Vol. 21, No. 1, 2002, pp.59-65.
[4]	M. V. Lopez, M. Sabre, R. Gracia, J. L. Arrue and L. Gomes, “Tillage Effects on Soil Surface Conditions and Dust Emission by Wind Erosion in Semiarid Aragon (NE Spain),” Soil and Tillage Research, Vol. 45, No. 1-2, 1998, pp. 91-105. doi:10.1016/S0167-1987(97)00066-4
[5]	A. Kade and S. D. Warren, “Soil and Plant Recovery after Historic Military Disturbance in the Sonoran Desert USA,” Arid Land Research and Management, Vol. 16, No. 3, 2002, pp. 231-243. doi:10.1080/153249802760284784
[6]	G. Dirk and Y. O. Zvi, “Aeolian Dust Erosion on Different Types of Hills in a Rocky Desert: Wind Tunnel Simulations and Field Measurements,” Journal of Arid Environments, Vol. 37, No. 2, 1997, pp. 209-229. doi:10.1006/jare.1997.0282
[7]	K. Michels, M. V. Sivakumar and B. E. Allison, “Wind Erosion Control Using Crop Residue. Effects on Soil Flux and Soil Properties,” Field Crops Research, Vol. 40, No. 2, 1995, pp. 101-110. doi:10.1016/0378-4290(94)00094-S
[8]	T. Wang, “Remote Sensing Monitoring and Assessing Sandy Desertification: An Example from the Sandy Desertification Region of Northern China,” Quaternary Sciences, Vol. 2, 1998, pp. 108-118.
[9]	T. H. Zhang, H. L. Zhao, S. G. Li, F. R. Li, Y. Shirato, T. Ohkuro and I. Taniyama, “A Comparison of Different Measures for Stabilizing Moving Sand Dunes in the Horqin Sandy Land of Inner Mongolia, China,” Journal of Arid Environments, Vol. 58, No. 2, 2004, pp. 203-214.
[10]	F. R. Li, L. F. Kang, H. Zhang, L. Y. Zhao, Y. Shirato and I. Taniyama, “Changes in Intensity of Wind Erosion at Different Stages of Degradation Development in Grasslands of Inner Mongolia, China,” Journal of Arid Environments, Vol. 62, No. 4, 2005, pp. 567-585. doi:10.1016/j.jaridenv.2005.01.014
[11]	Z. B. Dong, G. T. Chen, X. D. He, Z. W. Han and X. M. Wang, “Controlling Blown Sand along the Highway Crossing The Taklimakan Desert,” Journal of Arid Environments, Vol. 57, No. 3, 2004, pp. 329-344 doi:10.1016/j.jaridenv.2002.02.001
[12]	J. Ren, L. Tao and X. M. Liu, “Effect of Different Microhabitats and Stand Age on Survival of Introduced Sand-Fixing Plants,” Journal of Arid Environments, Vol. 51, No. 3, 2002, pp. 413-421. doi:10.1006/jare.2001.0967
[13]	FUJIYOSITAKAO, “Integrated Areas to Prevent the De- sertification, Chemistry and Industry,” Chemical Society of Japan, Vol. 61, No. 2, 2008, pp. 103-107.
[14]	J. Yang, F. Wang, L. Fang and T. W. Tan, “Synthesis, Characterization and Application of a Novel Chemical Sand Fixing Agent-Poly(Aspartic Acid) and Its Composites,” Environmental Pollution, Vol. 149, No. 1, 2007, pp. 125-130. doi:10.1016/j.envpol.2006.12.021
[15]	R. A. Siddiqi and C. J. Moore, “Polymer Stabilization of Sandy Soils for Erosion Control,” Transportation Research Record, No. 827, 1981, pp. 30-34.
[16]	M. L. Shawqui and A. Neaz, “Effect of new Soil Stabilizers on the Compressive Strength of Dune Sand,” Construction and Agents, Vol. 12, No. 6-7, 1998, pp. 321- 328.
[17]	Z. Dong, L. Wang and S. Zhao, “A Potential Compound for Sand Fixation Synthesized from the Effluent of Pulp and Paper Mills,” Journal of Arid Environments, Vol. 72, No. 7, 2008, pp. 1388-1393. doi:10.1016/j.jaridenv.2008.02.008
[18]	Z. S. Wu, Z. R. Wu, K. Iwashita and H. Inagaki, “Devel- opment of Sand Stabilization and Greening Technique with Osrganic Slurry Containing Hydrophilic Polyurethane,” The 4th International Workshop for R&D Clustering among China, Japan, Korea in Eco-Materials Processing (CJK 2008)(Keynote), Hakone, 2008.
[19]	Z. R. Wu, K. Iwashita, Z. S. Wu and H. Inagaki, “Re- search on Sand Dune Fixation and Green Vegetation of a Novel Chemical Material and Construction Method of Demonstration Areas Around Qinghai Lake,” The Report of METI NEDO Project, H19 NO. 0710002, Year.
[20]	Z. R. Wu, K. Iwashita, Z. S. Wu and H. Inagaki, “Experimental Study on Evaluation and Control of Ultraviolet Resistance of Sand Stabilized with Organic Slurry Containing Hydrophilic Polyurethane,” Journal of the Japan Society of Material Science, Vol. 57, No. 11, 2008, pp. 1167-1172. doi:10.2472/jsms.57.1167
[21]	Z. R. Wu, Z. S. Wu, K. Iwashita, W. M. Gao and H. Ina- gaki, “UV Irradiation Degradation Control of Sand Stabi- lized with Organic Slurry Containing Hydrophilic Poly- urethane,” Journal of the Japan Society of Material Science, Vol. 60, No. 3, 2011, pp. 235-239. doi:10.2472/jsms.60.235
[22]	Y. M. Wang, W. W. Chen and W. F. Han, “Simulation Study on Resistances to Wind Erosion of New Polymer Material in Sand Fixation,” Journal of Soil and Water Conservation, Vol. 19, No. 6, 2005, pp. 12-14.
[23]	Q. C. Chen, P. F. Jiang and T. W. Lei, “Wind tunnel Experiment on the Impacts of Polyacrylamide on Wind Erosion of Loosen Soil Materials,” Transactions of the CSAE, Vol. 22, No. 10, 2006, pp. 7-11.