Studies On The Degradation Of Dyes Wastewater By Environmental Friendly Mechanochemical Method

The treatment of dyes wastewater by adsorption-mechanochemical method overcoming the problem of hard-regeneration of adsorbents in tradictional absorbed way and the defect of the secondary pollution and high energy consummation,is a new and haress technology.NiO was prepared by a simple method in this dissertation, and by taking NiO as an object of study,we had studied to treat dye wastewater on NiO by mechanochemical method, and the results indicated that this method can degradate effectively dyes wastewater.The main contents and results are presented as follows:1.Different oxides had been prepared,and were used in experiments by adsorption and milling with turquoise blue KN-G, judging criteria by the decolorization rate and removal of CODcr,selecting oxides with high adsorption capacity and mechano-catalysis capacity as study object. The results indicated that the equilibrium adsorption quantity of dye on NiO was far better than other oxides on turquoise blue KN-G and reactive black KN-B,CODcr removal rate of turquoise blue KN-G was 99 % after milling.2.The study on adsorption characteristics of NiO indicate that adsorption quantity of NiO on reactive dyes than others was better, the saturated adsorption capacity of NiO was respectively 169.9 mg/g and 208.3 mg/g,the adsorption of NiO was a spontaneous process, and high temperature can accelerate adsorption of NiO, the adsorption of NiO was better when pH of solutions was neutral situation.3.The degradation of turquoise blue KN-G by mechanochemistry method was carried out by using a palanetary mill with oxides of NiO.The results showed that the best technological parameters included: milling time:15 hours, speed of ball milling:500 r/min;the best effect of material ratio(the ratio on quality of NiO and turquoise blue KN-G):15 and mass ratio of the stuff to mill to the ball: 18; grinding ball: glass beads.Under these conditions, turquoise blue KN-G was degaradated.and that the removal of CODcr was 95 % indicated good effect.4. The degradation of dyes by mechanochemistry method was carried out by using a palanetary mill with oxides of NiO after adsorption. The results indicated that the effect before adsorption was better than after adsorption both saturated adsorption and nonsaturated adsorption. the removal of CODcr of turquoise blue KN-G was only 71 %,while reactive black KN-B was 85 %. After was used repeatedly 5 times, regeneration of NiO adsorption capacity decreased to 40 %. 5.Mechano-catalysis mechanism of mechanochemical was also discussed.NiO by violent ball-milling produced free electrons,which combined with H+ produced hydrogen free-radical, the benzene ring of dyes can be degraded by nucleophilic substitution of hydrogen free-radical and dyes.