Study On Treatment Of Wastewater Containing Lead With Modified Sepiolite By Microwave

In recent years, the rapid growth in electric vehicle industry have contributed tothe expansion and development of the battery industry, Lead pollution problem isincreasingly serious and showed a trend of rising every year. This got much attentionin social circles. Comprehensive treatment of lead pollution wastewater has become aserious problems that cannot be ignored for the government and relevant industries.The adsorption method is an effective method to remove heavy metals from thewastewater. Seek strong adsorption performance and low-cost adsorbents is one of thehot spot of researches of heavy metals wastewater treatments. It’s meaningful to studyeconomic efficiency methods for lead wastewater treatment.In this paper, cheap sepiolite as test material was modified by treatment withmicrowave irradiation combined with iron modification method. The effect factorssuch as the modified methods, adsorption process conditions, microwave irradiationpower and time, the addition amount of ferrous sulfate were discussed, as well as theinfluencing factors to treat the wastewater containing lead. The optimal processconditions was obtained by response surface analysis. The results are as follows:(1) Using ferrous sulfate as a modifier, the adsorption performance of theobtained modified sepiolite modified by microwave irradiation have been improved.Compared with the raw sepiolite, modified sepiolite significantly enhancedadsorption of Pb2+in wastewater. With the increase of iron content In modifiedsepiolite, the removal ability of modified sepiolite have also increased. Experimentsshowed that in the process of modification the ferrous sulfate content is one of themost important factors. The results of the response surface analysis showed that thetheoretical value of removal rate can reach99%when the modified conditions for theirradiation power is250W, irradiation time is7min, and the ferrous sulfate was added2.68%to Wastewater containing lead. The actual value of removal rate was95.5%.(2) In the adsorption process, there are some interaction among dosage, shakingtime and pH, the last two factors play a key role in wastewater removal rate effect.When pH value is greater than3, the adsorption properties of raw sepiolite declined significantly, but those of modified sepiolite decreased less, the modified sepiolite hasshown higher adaptive ability to pH value. In the adsorption process when shakingtime was larger than a certain value, the removal rate of wastewater containing leadwas not be increased. The results of response surface analysis showed that thetheoretical value of removal rate can reach99%in adsorption system the optimumconditions for modified sepiolite when the dosage of modified sepiolite is0.5g, theshake time is27.18min, the pH of water solution is3. The highest actual value ofremoval rate can reach96.96%; the optimum conditions for raw sepiolite is thedosage of raw sepiolite is0.63g, the shake time is77.33min, the pH of water solutionis2.61, and the theoretical value of removal rate can reach97%, the highest actualvalue of removal rate can reach95.42%.(3) The structure of modified sepiolite was characterized by SEM-EDS. Theresults showed that the surface of modified sepiolite became roughness and wascovered with a layer of filamentous structure on the surface, the block structure alsoreduced; The energy spectrum analysis showed that iron content in the modifiedsepiolite increased, but the C, Ca contents reduced, and increased also the specificsurface area and surface hydroxyl number of modified sepiolite, this is the mainreason for the modified sepiolite to enhance its adsorption capacity.