Study On Industrial Wastewater Advanced Treatment By Using Modified Attapulgite

Recently,the environmental management has been under intense pressure,due to the rapid development of the industry.It is frequently observed for the small and medium sized enterprises that they discharge pollutant beyond pollution limits or over pollution quantity,because of lack of sewage treatment equipment or funding,and the imperfect drainage equipment.Attapulgite,as natural nano-material,with the feature of large specific surface area,friendly to environment and easily to recycle,has been widely used in the Fenton-like reaction and adsorption.Natural attapulgite needs to be modified to improve its application efficiency,because the adsorption and ion-exchange ability of natural attapulgite are limited.Seeking new highly efficient heterogeneous catalysts,which has a wide working pH and can be easily recycled,has been the research focus of Fenton-like reaction.This paper prepared absorbent HATP and heterogeneous catalyst Fe(?)-HATP through the acid modifying attapulgite and ferric chloride immobilizing attapulgite,discussed the optimal preparation condition,contrasted the structure changes between HATP,Fe(?)-HATP and ATP;Further studied advanced treatment for pharmaceutical wastewater by the Fenton-like combing with adsorption reaction,with the absorbent HATP and heterogeneous catalyst magnetite,at the same time,found the optimal operating conditions;Besides,studied advanced treatment for printing and dyeing wastewater through the Fenton-like combing with adsorption reaction,with the absorbent HATP and heterogeneous catalyst Fe(?)-HATP,furthermore,determined the optimal operating conditions.The main research results are illustrated as follows:(1)the optimal prepared conditions for HATP:ATP was immersed in lmol/L sulfuric acid solution for 24 h,then was filtered and dried at 105 ?,grinded after 2 h.(2)the optimal prepared conditions for Fe(?)-HATP:take some HATP and Fe(?)-HATP in the m(HATP):n(FeCl3)=10:7(g/mmol),prepared HATP into suspension and added FeCl3 solution drop by drop under ultrasonic treatment.Stirred the solution for 4h by stirring device,then filtered and washed to remove superfluous FeCl3.The filter cake was prepared to solution and the pH was adjusted to 7.The solution was filtered and washed again,the filter cake was dried at 105? Afterthat,grinded and roasted it for 2h at 300?.(3)The FTIR and XPS characterization results showed that the acid treatment could reduce the ATP carbonate carbon and carboxyl carbon content of ATP significantly;Fe(?)of the Fe(?)-HATP existed as the form of Fe2O3.(4)the optimal reaction conditions of advanced treatment for pharmaceutical wastewater with the absorbent HATP and heterogeneous catalyst magnetite:solution pH was 5,the dosage of H2O2 was 0.25 ml/L,the dosage of magnetite was 200mg/L,the reaction temperature was 40 ?,reaction time was 3 h,and the optimal dosage of adsorbent HATP was.150mg/L when the solution pH was 3.Eventually,the removal rate of CODcr was 78.38%?79.14%,the removal rate of total nitrogen was 71.53%?77.43%,and the removal rate of total phosphorus was 97.74%?98.10%.(5)the optimal reaction conditions of advanced treatment for printing and dyeing wastewater through the Fenton-like combing with adsorption reaction,with the absorbent HATP and heterogeneous catalyst Fe(?)-HATP:the solution pH was 6,the dosage of H2O2 was 0.3 ml/L,the dosage of heterogeneous catalyst Fe(?)-HATP was 350 mg/L,the reaction temperature was 40 ?,the reaction time was 6 h,and the optimal dosage of adsorbent HATP was 150 mg/L when the solution pH was 3.Ultimately,the removal rate of CODcr was 79.87%?80.94%,the removal rate of total nitrogen was 68.59%?70.93%,and the removal rate of total phosphorus was 79.31%?83.33%.(6)through repeated tests for heterogeneous catalysts,magnetite could be recycled three times,the catalytic efficiency was 59.48%when it was recycled for the third time;Fe(?)-HATP could be recycled for four times,the catalytic efficiency was 62.47%when it was recycled for the fourth time.(7)The reagent cost of advanced treatment for pharmaceutical wastewater was 1.01yuan/m3,and 1.36yuan/m3 for printing and dyeing wastewater.