| Desertification is one of the most serious ecological and environmental problems in our country and even the world today.The area of desertified and desertified land is also increasing year by year,which seriously affects the development and construction of the national economy and reduces the quality of the national living environment.Therefore,sand prevention,sand fixation,and sand control are an environmental problem that needs to be solved urgently in our country.The 14 th Five-Year Plan of China also clearly points out that it is necessary to promote green development and promote the harmonious co-existence between man and nature.The northern sand prevention belt project is also listed as one of the important ecological system protection and restoration projects.At present,the sand fixation methods are basically engineering sand fixation,biological sand fixation,and chemical sand fixation.Biological sand fixation requires a lot of manpower and material resources,and biological sand fixation is slow and requires high environmental requirements.Chemical sand fixation has been rapidly developed in recent years due to its simple construction and quick results.The new chemical sand-fixing material should not only have certain water absorption and water retention properties,but also have good bonding ability,so that the loose sand particles can be tightly bonded.In this thesis,two kinds of water-retaining and sand-fixing materials were prepared by using natural biomass materials and white carbon black prepared from waste oil shale semi-coke as raw materials for water-retaining and sand-fixing engineering.The main research contents and results are as follows:(1)A novel sa-son seed gum grafted acrylic acid(SSG-g-PAA)superabsorbent resin was prepared by aqueous solution polymerization using sa-son seed gum(SSG)and acrylic monomer(AA)as raw materials and ammonium persulfate(APS)as initiator.The prepared SSG-g-PAA resin has a good three-dimensional network structure.The optimal conditions for synthesizing SSG-g-PAA superabsorbent resin are determined as m(SSG)/m(AA)=0.12,m(APS)=0.014,m(crosslinking agent)/m(AA)=0.003,and the neutralization degree of acrylic acid is 65%.Especially,the swelling rates of SSG-G-PAA resin in distilled water and 0.9 wt% Na OH solution were 1025 g/g and 139 g/g,respectively.(2)The tara gum grafted acrylic acid/silica(TG-g-PAA/silica)composite water-absorbent resin was prepared by cross-linking polymerization with ammonium persulfate(APS)initiator and N,N methylene bisacrylamide(MBA)crosslinking agent using tara gum(TG),acrylic acid(AA),oil shale semi-coke-based white carbon black(Silica)as raw materials.The structure was characterized by FTIR,SEM and TGA,and the results showed that the grafting polymerization of tara gum and acrylic acid was successful,and it was uniformly mixed with silica.The effects of the content of semi-coke based silica,p H value and surfactant on the swelling ability of the TG-g-PAA/silica composite water-absorbent resin were investigated.The results show that the absorbent resin has good swelling property and p H stability.(3)The tara gum grafted acrylic acid/silica(TG-g-PAA/silica)composite water-absorbing resin is used as a new type of sand fixation material.The effects of different content of sand fixing agents on the compressive strength of sand fixing samples were investigated,and the thermal stability,freezing-thawing aging resistance,ultraviolet aging resistance and water retention performance of sand fixing samples were evaluated in detail.The experimental results show that the compressive capacity of the new sand-fixing material can still reach more than 90% of its initial value after 20 days of anti-aging test. |
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