Multicore Composite Flocculant And Combinations Thereof, The Theoretical And Applied Research

The pollution of wastewater to environment is becoming more and more serious. Traditional coagulation and chemical oxidation processes are not already efficient to treat various low biodegradability organic wastewaters. Although there are some advanced treatment technologies with which better effect can be achieved, it is difficult to be applied widely because of expensive run expenses and complicated operation processes. In order to enhance the remove of pollution substance, it is a practical way, based on improving water treatment efficiency, to treat the low biodegradability organic wastewaters with the combined processes of potential new techniques and traditional water treatment process. It is very important to treat some organic industrial wastewater and territorial sewage which are difficult to treat.In this paper, based on the excellent coagulation efficiency of new multi-core compound inorganic polymer flocculant, the combined process of coagulation, Fenton oxidation process which is already developed well and applied widely, and microwave treatment process is adopted to treat oil-containing wastewater, printing and dying wastewater, and landfill leachate. Not only the applied field of microwave energy is developed, but also it provides a new way to treat other low biodegradability organic wastewaters.Firstly, preparation processes of some flocculants and their coagulation performances are investigated in detail in this paper. A new multi-core compound inorganic polymer flocculant (PMSi) is composed based on preparation experience of some simple-composition flocculant and PFASSi. During the preparation of PMSi, reagents of C and D which will be helpful to oxidation and sedimentation respectively are added to improve decolorization and organic substance removal effect. The optimal preparation conditions of PMSi are that the content of SiO₂ is 2.2%, Al/Fe/Si molar ratio is 10:5:1 and the basicity is 2.0. When PMSi is used to treat printing and dying wastewater, and landfill leachate, the dosage of PMSi is lower than those of others and the adaptability of PMSi to pH is better.Then, microwave irradiation enhanced coagulation and Fenton oxidation process are investigated in detail. The study result of microwave irradiation enhanced coagulation process show that the process of irradiating with microwave firstly and then with coagulation is more efficiency to treat oil-containing wastewater than that with coagulation firstly and then with microwave, and when dying wastewater and landfill leachate are treated with microwave irradiation and coagulation process simultaneously, the treatment effects will become better. The study result of microwave irradiation enhanced Fenton oxidation process shows that, no matter what oil-containing wastewater, printing and dying wastewater and landfill leachate, better treatment effect will be achieved with microwave irradiation firstly and then with Fenton oxidation process, with which organic substance and chromaticity can be removed easily.The treatment results of oil-containing wastewater, printing and dying wastewater and landfill leachate with microwave irradiation enhanced Fenton oxidation coupling coagulation process show that not only all pollution items are improved, but also the biodegradability of all are increased greatly. In addition, when microwave irradiation process is introduced to enhance coagulation and Fenton oxidation process respectively, not only the dosages of the flocculant (PMSi), oxidant (H₂O₂) and catalyzer (Fe²⁺) are all reduced obviously, but also the treatment times of whole coagulation sedimentation and Fenton oxidation processes are decreased, which is very important and practical to promote the industrial application of this combined process in future.The homogeneous nucleation discussion shows that PMSi possesses the excellent homogeneous nucleation performance. Many crystal nucleuses are formatted when PMSi is added into wastewater. It makes lots of floccules sedimentation to format and granule floccules to grow rapidly, which makes the floccules close-grained, big-bodies and fast-sedimentation-rate. Multiphase copolymer is formatted when reagents of C and D are adopted to prepare PMSi, in which all kinds of effectual components are copolymerized with Al and Fe. When the aggregation reactions are happened, Fe is transferred into crystallite phase which delays the formation of 6-FeOOH sedimentation in acid solution and keep the great stability of PMSi.HPLC analyses results of phenol solution and GC-MS analyses results of oil-containing wastewater with different microwave irradiation enhanced processes show that the effect of microwave irradiation enhanced coagulation process embodies mainly on that breaking emulsification speed and effect are heightened, and coagulation sedimentation speed and the removal effect of turbidity are increased, and some organic substances are removed through coagulation process due to their surface performances are changed under the condition of microwave irradiation. But organic substances nearly can not be removed directly with microwave irradiation enhanced coagulation process. On the other hand, the removal effect of most organic substances with microwave irradiation enhanced Fenton oxidation process is very good and organic substances are mineralized greatly, and some organic substances which can not removed completely are degraded, and their concentrations are reduced greatly. Organic substances are almost removed with microwave enhanced Fenton oxidation coupling coagulation process. Their stable structures are destroyed, decompounded and even mineralized.The study results of the synergetic effect of microwave enhanced Fenton oxidation process and microwave enhanced coagulation process shows that microwave irradiation enhanced Fenton oxidation coupling coagulation process embodies fully the synergetic effect among microwave irradiation, Fenton oxidation and coagulation.The study result of the non-thermal efficiency of microwave shows that high frequency microwave electromagnetism field can make the polarity molecule in solution phase rotate with high speed, which induces microwave thermal efficiency to change systematic thermodynamics function. The non-thermal efficiency of microwave embodies mainly on the special effect of microwave electromagnetism field to the structure of organic substance. The electromagnetism field can reduce the chemical bond intensity of molecule through some field effects of polarization effect, hydrogen bond distortion and activation energy change, and heighten the oxidation effect of hydroxyl radical degrading organic substance.