Preparation And Properties Of New Inorganic-Organic Composite Polymer Flocculants

As we all know, water is the source of the lives, water pollution is theroot of environment pollution. Humans, animals and plants will be subject tothe harms from water contamination. Waste drilling fluid is a major source ofpollution in the petrochemical industry, which is a stable suspension system,containing a variety of toxic organic additives and inorganic salts, alkalisubstances, and the amount is very large and difficult to treatment. If the wastedrilling fluid is not treated to emission, it will be causing serious harm towater source and soil. With the development of the oil industry, the problemsof pollution caused by waste drilling fluid are being more and more importantto people, and the treatment of the waste drilling fluid also has been developed.Many countries in the world have established the appropriate legal provisionsto promote environmental protection.Water pollution treatment cannot be avoided to use the water treatmentchemicals, the largest amount of which is flocculants. The types of flocculantsare very large, as many as two or three hundreds species. The flocculants canbe classified to inorganic flocculants, organic flocculants and microbial flocculants according to the chemical compositions. There also have mixedand composite flocculants between the inorganic and organic flocculants.Because each flocculant has its advantages, disadvantages, and applicationranges, a large number of researches have been shown that two or more thantwo flocculants by mixing or reaction to a composite flocculant being used oradded respectively can overcome many shortcomings of just using one singleflocculant, realize complementary advantages, and reduce the water treatmentcosts and also improve the flocculation effect at the same time, thedevelopment and applicaltion of composite flocculants have become one ofthe research focus in the area of wastewater treatment.Inorganic–organic composite polymer flocculant, which has the quick gelbroken performance of inorganic flocculants, the adsorption bridgingcapability of organic polymer flocculants, and low doses, strongerdecolorization ability, good turbidity removal performance, especially thecomposite flocculants formed by inorganic nano–oxides and natural polymerswith a wide source of raw materials, low cost, non–toxic, and easilydegradable, is a new and great potential for development of water treatmentchemicals. Use of inorganic–organic polymer composite flocculant onsolid–liquid separation for waste drilling fluid is suitable for large–scaleintroduction because of less equipment, simple operation, and low cost. Torealize the research objective of the water content of the filtration cake lessthan30%after solid–liquid separation of waste drilling fluid, four new inorganic–organic composite polymer flocculants were developed in thispaper; the main work is as follows:1. The basic physical and chemical properties of waste drilling fluid,which from one well of Shengli Oilfield, were analyzed,and the right gelbreaker used for the waste drilling fluid treatment was filtered out.2. Inorganic–organic composite polymer floccualnts SSAD and CSSADwere prepared by the reaction of corn starch (St),acrylamide (AM) and(2–methacryloyloxyethyl) trimethyl ammonium chloride (DMC) with apreviously prepared SiO2sol from water glass by using in-situcopolymerization process, and the preparation conditions were optimized;without the function of gel breaker AlCl3, when the dose of SSAD was0.5%,the flocculation performance was the best, solid water content was20.78%,solid weight removal ratio was92.80%, the flocculation performance ofCSSAD was the best in a dosage of0.4%, solid water content and solidremoval ratio were19.85%and95.89%, respectively.3. Al2O3colloid prepared by AlCl3was modified on surface with KH570,then the surface modified Al2O3colloid with AM and DMC were used toprepared the cationic inorganic–organic composite polymer flocculantCAPAM, and the preparation conditions of CAPAM were optimized; CAPAMwas used for waste drilling fluid treatment in a dosage of0.3%with AlCl3,solid water content reached a minimum value of19.86%, and solid removalratio was up to98.60%; without the function of gel break, the minimum water content was20.15%at a dosage of0.5%, the maximum solid weight removalwas95.30%at a dosage of0.4%.4. Anionic composite flocculant SSCMC was prepared by the reaction ofcorn starch, sodium carboxymethyl cellulose (CMC) with a previouslyprepared SiO2sol from water glass, and the preparation conditions of SSCMCwere optimized; the flocculation performance of SSCMC was best when thedose of SSCMC was0.4%without of the function of gel breaker, and solidwater content and weight removal ratio were28.08%and89.34%,respectively, and the transmittance of the upper clear layer was up to96.36%.5. The four prepared composite flocculants and the commercializationflocculants were used for waste drilling fluid treatment; the results showedthat the flocs formed by composite flocculants were large, dense and rapidsedimentation, in which CSSAD had the highest oil removal, turbidityremoval, organic matter removal, and CODCr removal, and the value were95.12%,98.80%,96.54%, and99.67%, respectively; SSCMC had the highestCr, Cd and Pb removal, and the value were84.84%,88.30%,89.29%,respectively; CSSAD had the best flocculation and dewater performance withthe lowest solid water content of19.85%and the highest solid removal of95.89%, followed by CAPAM and SSAD.6. The flocculation mechanism of inorganic–organic compositeflocculants was researched from the components and properties of wastedrilling fluid, and the acidification coagulation and self–assembly and settlement mechanism was first proposed to explain the flocculation action onwaste drilling fluid.