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Preparation Of Activated Carbon From Pyrolusite-added Herb Residues And Its Adsorption Of Heavy Metals In The Waste Water

Posted on:2013-02-27Degree:MasterType:Thesis
Country:ChinaCandidate:J HuangFull Text:PDF
GTID:2251330425986704Subject:Environmental Science
Abstract/Summary:PDF Full Text Request
In recent years, with the development of traditional Chinese medicine and theenhancement of people’s awareness of health, people from all fields at home and abroadare starting to focus on the research and exploitation of traditional Chinese medicineand its products. However, the waste residues are produced in the production process ofChinese medicine, it brings some thorny problems to the manufacturer, society andenvironment. Traditional ways for dealing with residues not only waste a lot ofresources, but also cause severe environmental pollution, especially soil, water and airpollution. Therefore, carrying out the comprehensive utilization of the residue resourceshas important practical significance, and has become a hot topic of present study.In this paper, the activated carbons were prepared from Notoginseng andOphiopogon japonicus residues using zinc chloride as the activator. The mainpreparation conditions such as the concentration of zinc chloride, ratio of solid to liquid,activation temperature and activation time on the influence of the actived carbon’sadsorption ability were studied. The optimum conditions for production of activatedcarbon were obtained from single factor and orthogonal experiments based on the yieldand iodine adsorption value of the products. And then, the products were used to adsorbtwo heavy metal ions (Cu2+and Pb2+) from simulated wastewater. In the meantime, theadsorption properties and adsorption isotherms were investigated.The experimental results were showed as follows: when the Notoginseng residueswas as raw material, the concentration of zinc chloride was3mol/L, the ratio of solid toliquid was1:2, the activation temperature was500℃, and the activation time was60min, the activated carbon had the yield of between40%and50%, as well as the iodineadsorption value of between910mg/g and940mg/g. Meanwhile, when theOphiopogon japonicus residues was as raw material, the concentration of zinc chloridewas5mol/L, the ratio of solid to liquid was1:2.5, the activation temperature was600 ℃, and the activation time was30min, the activated carbon had the yield of between35%and40%, as well as the iodine adsorption value of between1000mg/g and1055mg/g.The structure, surface morphology and performance of the two kinds of activatedcarbon were characterized by BET, SEM, TGA, FT-IR, O2-TPO and XRD. The resultsshowed that the activated carbon from Notoginseng residues mainly containedmesoporous structure, then had specific surface area of366.02m2/g under theexperimental conditions. Simultaneously, the activated carbon from Ophiopogonjaponicus residues mainly contained microporous structure, then had specific surfacearea of774.93m2/g under the experimental conditions.The two kinds of activated carbon were used for adsorption treatment of two heavymetal ions (Cu2+and Pb2+) from simulated wastewater, respectively. The adsorptionexperiment results showed that the produced activated carbon had a certain removalefficiency for the two heavy metal ions, but the activated carbon from Notoginsengresidues had a higher removal efficiency. The Langmuir and Freundlich adsorptionisotherm equations could simulate the adsorption behavior well. Finally, theregeneration of activated carbon that reached adsorption saturation was found they stillhad certain adsorption performance after regeneration with chemical reagents.In summary, this showed that the preparation of activated carbon from herbresidues by zinc chloride activation method can make residues converted to high addedvalue from low added value, reduce the environmental pollution and broaden the sourceof raw materials for production of activated carbon. The products that were used for thetreatment of heavy metals in wastewater could achieve a certain treatment effect.Therefore, producing activated carbon opens up new ways for the utilization of herbresidues and has social, economic and environmental benefits to some extent.
Keywords/Search Tags:herb residues, activated carbon, iodine adsorption value, heavymetals, adsorption
PDF Full Text Request
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