Study On Advanced Treatment Of Papermaking Wastewater By Photocatalytic Oxidation

Due to the complexity of composition,high concentration organic pollutant,is hard to biodegradable,papermaking waste water after conventional secondary biochemical treatment still cannot satisfy the relevant emission standard in our country,needs to be further depth processing.And the photocatalytic oxidation technology take the advantage of it's high reaction rate and less secondary pollution,good treatment effect,shows it potential applications in depth treatment of papermaking wastewater.In order to realize the papermaking wastewater discharging standard and recycle,this paper focus on the practical papermaking wastewater after biochemical treatment,two kinds of methods of photocatalytic oxidation treatment based on hydroxyl radicals and sulfate radicals are studied respectively for their effect,factors like wastewater p H,catalyst and the concentration,UV wavelength,light intensity,oxidation time was studied for their influence and optimization,the reaction kinetics and organic pollutants degradation mechanism were studied.The following is the main achievements of this research,(1)pH of waste water,kind of catalyst,catalyst concentration,light intensity and ultraviolet wavelengths are important factors affecting the effects of photocatalytic oxidation reaction.In view of the actual research paper in the biochemical process of above factors is found that under acid condition(p H = 4),the dosage of Ti O2 is 20 mmol/L,in the UV wavelength of 254 nm and 365 nm UV lamp of 150 W continuous illumination 90 min,the process got the best reaction conditions.But it's still cannot achieve discharge standards.(2)The treatment of papermaking wastewater by using UV/PMS photocatalytic system,also research wastewater p H,light intensity,light wavelength,the influence of the dosage of treatment effect.Found in the actualpaper biochemical effluent p H 3,dosage of PMS is 3 g/L,the intensity of 150 W and the wavelength of 254 nm UV lamp irradiation,the effluent can reach the standard emission.(3)By fitting the reaction kinetics of two kinds of photocatalytic system,the kinetics of UV/Ti O2 reaction system fit for the second-order reaction,UV/PMS reaction system of first order reaction kinetics in response;The UV/PMS reaction system of reaction rate is much higher than the former,Furthermore,according to the results of GC-MS analysis,petroleum hydrocarbons,phthalic acid esters(PAEs),polycyclic aromatic hydrocarbons(PAHs),aniline and other SVOCs are the major organic pollutants in pulp and papermaking industry wastewater,and show different degree in degradation after photocatalytic oxidation treatment.