Research On Coating Pollution Abatement And UV-curable Acrylate Coating Synthesis Based On Cleaner Production

Known as "the beautiful coat" of coating, is widely used in industry, agriculture and human daily life. It has become an important product for beautifying the environment and life, and also been the indispensable important supporting engineering materials in national economy and defense industry. Increasing attention to the problems of environmental pollution on a global scale makes the coating industry facing the huge challenge, for example, coating pollution, toxicity and pollution problem produced during coating production process have been paid more and more attention. Coating composition is very complicated, containing many kinds of organic compounds. Wastewater non-standard discharging during production process, dispersed coating as well as coating waste packaging often become mobile pollution sources. There are much equipment for coating production need to wash, such as paint mixing cylinder, filters and filter medium, storage tank and storage tank; besides, production, transportation and spill, leak or accident of material in storage places all need to be cleaned, and this part of the washing water is also an important part of wastewater from coating industrial production. Production and utilization of coating are likely to cause heavy metal pollution in the process. Since inorganic dyes are derived from natural minerals and usually through a series of physical-chemical reaction, it is hard to avoid placing trace impurities of heavy metals. In addition, all kinds of additives for facilitating production, such as catalyst, antifouling agent, matting agent and various impurities contained in the packing. In addition, paint supplies such as car after scrapped, the film contains will follow these heavy metals into the environment and cause heavy metal pollution of water bodies, and harm to human beings.Based on the economic and environmental microbial method, organic pollutants and heavy metal from wastewater of coating were handled in this study, and put forward several kinds of new, environmentally friendly UV curing coating synthesis technology, realized the requirement of clean production. Specific research work and achievements of this paper includes the following six parts:Firstly, this article puts forward the microbial flocculant compounding with polyaluminium chloride (PAC) for coating wastewater treatment technology. Our lab used red aureus producing flocculant, and compared with polyaluminium chloride compound, in order to govern high concentration of COD and chromaticity in wastewater of coating industrial; then the response surface method (RSM) was employed to conduct statistics design and data analysis for experiment, optimize the flocculation conditions, farthest remove COD and chromaticity in coating wastewater. Experiments found that microbial flocculant and pH value had the decisive role in the realization of the flocculation. Ca2+ can promote flocculating sedimentation and removing of organic pollutants by bridging, and adsorption of excessive Ca2+ on functional groups with negatively charged in microbial flocculant molecular could reduce the combination between colloidal particles and microbial flocculant. Besides, under high dosing quantity of microbial flocculants condition, a small amount of PAC could achieve significant effectiveness. Experimental results supported that the best flocculation conditions of microbial for coating wastewater were:flocculant 47 mg/L, PAC 39 mg/L, pH 8.2, CaCl2 0.38 g/L, and 210 r/min of stirring intensity. At the best flocculation conditions, the removal rate of COD and chromaticity of coating wastewater was 77.6% and 68.9%, respectively.In the second part, monorhamnolipid and Tween 80, as the representative of the surfactants, were used to study the effect surfactant on the biodegradation of phenol in coating wastewater by Candida tropicalis CICC 1463 and pseudomonas ATCC AB93188, and their effectiveness was compared. The results show that rhamnolipid and Tween 80 had certain influence on phenol degrading bacteria. Rhamnolipid can enhance the growth of bacteria, and accelerate the biodegradation rate of phenol, these might be due to the formation of aggregates between rhamnolipid and phenol resulted in lowering free phenol concentration and thus reducing the toxic effect of phenol on bacteria. For Tween 80, the chemical surfactants inhibited the growth of bacteria since the logarithmic phases of bacteria were both delayed, it may be that the toxicity derived from phenol and Tween 80 co-inhibit the growth of the bacteria. For pseudomonas culture, Tween 80 had a negative effect on the degradation phenol, but the result was opposite for Candida tropicalis. This interesting phenomenon may be caused by the different tolerance of microbial species to phenol and Tween 80.We made use of Fe3O4 magnetic nanoparticles immobilized cutin enzyme adsorbing and degrading the DEHP derived from production process of coating wastewater in third part of article. Due to the structure of Fe3O4 magnetic nanoparticles can be bound support effect on the cutin of enzyme, resulting in the pH, thermal stability and storage stability of immobilized cutin enzyme were improved comparing with free cutin enzyme. When the reaction temperature was 30～50℃ and the pH value was 6.0～9.0, the use of immobilized cutin enzymes in the processing of DEHP could enhance the processing efficiency above 60%. The removal rate of adsorbing-degrading material with Fe3O4 magnetic nanoparticles immobilized cutin enzyme could reach 81%, the enzymatic hydrolysis was about 78%, and no secondary pollution in degradation products. Wider reaction temperature, pH value and the application scope of reasonable dosage ratio shows that immobilization cutin has good prospects in actual application. In processing the actual coating process of waste water containing a small amount of heavy metal ions, when the concentration of Pb2+ was 10 mg/L, the DEHP and Pb2+ treatment efficiency of immobilized cutin enzyme can maintain can achieve 68.4% and 21.6%, respectively. Recycling DEHP immobilized enzyme treatment up to 5 times, the processing efficiency can maintain 75%, while circulation use up to eight times, it still can maintain 70% processing efficiency. The results show that the immobilized cutin enzyme has a good reuse, and the improvement of enzymes utilizing efficiency reduces the use cost.Part 4 in this paper proposes a combination of agricultural waste rice straw and white-rot fungus phanerochaete chrysosporium to remove Pb2+ from coating wastewater containing Pb2+. In this part of the study, we studied the effects of different initial pH and Pb2+ concentrations on the absorption efficiency of the Pb2+, the biomass of phanerochaete chrysosporium, the production of oxalate and the changes in the rice straw structure.The experimental results show that after 21 days of solid-state fermentation, in the system with low initial concentration of Pb2+(100 mg/L and 200 mg/L), most of the free Pb2+ has been removed, with removal of 97.6% and 95.3% respectively; In the system with initial Pb2+ concentration of 100 mg/L, phanerochaete chrysosporium present the highest biomass, and the biomass decreased gradually along with the increase of initial concentration of Pb2+; Oxalate content decreased after the an increase at the beginning of the fermentation, and reached the maximum after 6 days (9 days in the initial concentration of Pb2+ 400 mg/L), under different initial concentration of Pb+, the system has a high concentration of oxalic acid, suggest that Pb+ may have the ability to promote phanerochaete chrysosporium’s production of oxalic acid.In the fifth part, bioremediation with phanerochaete chrysosporium was used to treat coating solid waste contains heavy metal lead.The study examines the changes in organic matter content, the microbial biomass carbon, lignin peroxidase and manganese peroxidase enzyme activity and the form of lead during the fermentation, and analyzes the effects of phanerochaete chrysosporium on the stabilization of lead.The research results show that the microbial carbon present a sharp rise and then decreased a little fllowed with some small variations, the addition of heavy metal lead inhibit the growth of indigenous microorganisms in the soil, but phanerochaete chrysosporium present certain resistance on heavy metal lead. After 42 days fermentation, the free and carbonate bounded form lead which is more toxic was transformed to the relatively stable state- residue lead, which means the treatment stabilized the heavy metal lead, confirmed the feasibility of bioremediation of coating solid waste contains heavy metal lead.In part 6, in order to overcome that uv-curable resins generally are of linear, we introduced the pentaerythritol with four functional space structure. Based on 2, 4-toluene diisocyanate, we synthesized two kinds of acrylic light cure resins with four functional groups. These acrylic light cure resins have good stability, excellent mechanical properties, and are of reactants and the low cost, wide application, conducive to industrial large-scale production. These two kinds of resin after photo-initiation would form mesh three-dimensional structure, thus having high mechanical strength, high hardness, good toughness and high resistance to wear, can be used as a crosslinking agent and wear-resisting UV coating resin. On the other hand, we introduced the dipentaerythritol (DPE) with six functional groups, synthesized a kind of high functionality UV curing urethane acrylate, which is abrasion resistance, scratches prevent, weather-proof and anti yellowing. DPE has typical star structure, big space structure, large shielding effect, which make the ester base is very stable. DPE can make up for the alkyd resins’ faults such as low resistance to water, moisture and alkali. Double cropping acrylate resin based coating can be quickly solidified under UV irradiation to form a coating layer, which is abrasion resistance, anti scratch, weather resistance and transparent. This coating can be used for the building glass, outer layer of other coatings and oil industry. The high functionality can accelerate the UV curing speed.This paper used different bioremediation methods to biodegrade organic pollutants or remove heavy metals deriving from the process of coating production and application, and introducing spatial structure to synthesize neotype principal part of coating synthesis. Due to the advantage of the new coating, the cleaner production of paint can be realized easily, and the environment pollution caused by coating production in the early days can be effectively governed through the above research methods. The study laid a theoretical foundation for the realization of the goal of cleaner production in coating industry.