Ultrasonic Ink Wastewater

Ink wastewater,a kind of complex,high organic content and hardly degradable wastewater,is still the focus point for environment field. Ultrasonic irradiation is a novel and friendly wastewater treatment technology in recent years.Based on these characteristics,the combined technology based on ultrasonic and coagulation,Fenton oxidation was used to treat the organic pollutants of ink wastewater.This paper studies the influential factors of degradation,synergetic effects and kinetics. Then,this paper selects the typical organic pollutants of ink wastewater as model pollutant,and move on to the study of factors in ultrasonic degradation,in order to gain insight into the ultrasonic degradation rules of ink wastewater.Coagulation combined with ultrasonic was used as pretreatment technology.As a result,it indicates that above 85%of CODcr removel rate and 90%of decolorizing rate was achieved after treating the wastewater with AlCl₃·6H₂O as coagulant with a dosage of 0.3g/L,at pH value 7.89,ultrasonic irradiation time 2min,and PAM as coagulation aid with a dosage of 0.8mg/L.It also shows that ultrasonic irradiation has some effect in the coagulation process,but it is not obviously.After the pretreatment,the rest CODcr is between 800～1000mg/L,It needs further treatment.After pretreatment,ink-wastewater is treated under the US/Fenton system.The effect factors of Fenton oxidation and ultrasonic irradiation on the degradation of the organic pollutants such as pH values, nFe²⁺/nH₂O₂,H₂O₂ concentration,ultrasound frequency and power were studied.The results showed that there was an optimal value of Fe²⁺ and H₂O₂ concentration.The degradation rate was increased with increasing ultrasonic power and frequency,but the effect of frequency was little.It was decreased with increasing pH value.Compared with single Fenton oxidation technology,the combined technology based on ultrasonic irradiation and Fenton oxidation can improve the removal rate of CODcr and color on the optimal conditions.The removal rate may reach to 81.4%,100.0%after 240min reaction,more than 16.0%and 5.5%better than that by only using the technology of the Fenton oxidation.The degradation of ink-wastewater by combined technology could decrease the Fenton reagents dosage and reaction time and it could be described by first-order and has obvious synergetic effect during 60min.The aim is to gain insight into the ultrasonic degradation rules, representative organic pollutants of ink-wastewater just like organic solvent m-xylene and azo dye MX-5B were chosen.The results show that the organic pollutants of ink-wastewater,m-xylene and azo dye MX-5B can be degraded effectively and rapidly.They degradation rate both increased as increasing ultrasonic power,but the effect of frequency is different.Between 200 kHz-800 kHz,the optimal frequency for m-xylene is 806.3 kHz,but 418.3 kHz for MX-5B,which suggests that selection of frequency,is collected with structure and property of organic pollutants. More,direct pyrolysis inside the collapsing bubbles has an important role in m-xylene ultrasonic removal,but radical oxidation controlled the ultrasonic decompose of MX-5B.In addition,m-xylene and MX-5B ultrasonic removal was both observed to behave as pseudo-first-order kinetics under different experimental conditions tested in the present work.