Removel Experimental Researching On Humic Acid In Water By Formation Compound Mg-Al Hydroxides

Today humic acid pollution is very serious, widespread attention at home andabroad. The pollution of humic acid is very serious in our rivers, lakes and reservoirs.Humic acid is an important component of natural organic matter, the molecularstructure contains a large number of reactive groups, it is in the water, showing thephysical and chemical properties of the water body certain hazards. If the waste waterthat containing humic acid not treated, but directly emissions, will seriously affect theecological environment and endanger human health.Hydroxy-Mg-Al compounds （Mg_xAl_y（OH） z.nH₂O） in shape without finalize thedesign form, and has a large specific surface area, which is formed in the enhancedcoagulation process, and the high degree of polymerization of the aluminum-basedcoagulants conducive the formation of more hydroxyl magnesium aluminumcomposite.In water treatment process it can be softening water very well, pollutantsin the water have very good remove effect. This experiment simulated water samplecontaining humic acid is prepared in accordance with several different options, it usedthe coagulation method, were studied in the pH of7.5-11.2, Mg²⁺ion concentrationof18、48、60mg/L, Al department coagulants （PAC, AlCl₃） dosage of0.03-0.4mmol/L, studied the removal of humic acid in water. The paper also studied at pH9.7and10.5, Mg²⁺ion concentration of18,48mg/L, Al department coagulants （PAC,AlCl₃） dosage of0.10mmol/L instead of NaOH to adjust the pH with MgO, theformation of the Hydroxy-Mg-Al compounds in removing humic acid have differenteffects.The experimental results show that the pH value, Mg²⁺ion concentration,coagulant dosage and different alkaline substances to adjust the pH have an importantimpact on the outcome of the experiment, while the pH value is the most importantfactor. Through the experiment research we can know, used as a coagulant PAC formed when magnesium aluminum composite for the removal of humic acid issuperior to using AlCl₃coagulant, PAC is a high polymer, under certain conditions theHydroxy-Mg-Al particles which formed by PAC and Mg²⁺is bigger than AlCl₃andMg²⁺formed, for the removal of contaminants has a very positive role in promoting.Based on the findings of this thesis for the removal of humic acid obtained at pH10.5, Mg²⁺ion content of48mg/L, Al-coagulant dosage is0.10mmol/L, theformation of the hydroxy-Mg-Al compound for the removal of pollutants can achievethe best result.