Studied On The Absorption Of Heavy Metals From Aqueous Solution Using Composted Sludge As Absorbent

Biosorption is the use of micro-organisms to adsorb heavy metals is a new biological wastewater treatment technology. Such as the use of algae, bacteria, fungi as a biological adsorbent,they have a good adsorption of heavy metal removal.The line is compared to conventional activated carbon adsorbent, to economical, renewable performance, and ease of access and so on.Therefore,efforts to find some New biosorbent to activated carbon adsorbent to become an urgent task.In this paper, the adsorption properties of composted sludge for Cd2+ and Zn2+ were investigated using the batch method as a function ofpH,initial metal ion concentration,reaction time, particle concentration.The absorption rate of sludge composting with changes in solution pH,changes in pH2.5,when Cd2+andZn2+on the adsorption capacity is very small,pH,within the pH range of 2.5-4.5,,the adsorption capacity increased dramatically, within the pH range of 4.5-7.5,the adsorption capacity has gradually balance the trend.However;After pH 7.5,adsorption also has a downward trend;The rate of composting sludge adsorption rate is relatee to initial concentration.the adsorption rate increased when increase the initial concentration of heavy metals,which the final balance gradually.The study found that pre-adsorption 40min,absorption rate increased significantly in adsorption process,about 80% of the total adsorbed heavy metal ions were removed from the solution;adsorption time 60min,the adsorption equilibrium state.Study on the Cd2+ and Zn2+ adsorption kinetics, the results of the fitting analysis shows that composting the sludge can be carried out with two very good dynamic model fitting, fitting line has a good relationship.The results show that Pseudo-second Order model can describe the adsorption kinetics of the real process,and the adsorption rate of the adsorption process is affected by many factors.By Langmuir isotherm and Freundlich isotherm to describe the Cd2+and Zn2+adsorption process,the fitting correlation coefficient was above 0.9,and the Freundlich adsorption model better fitted.For more in-depth study on the heavy metal sludge composting process of the chemical nature.Examined before and after adsorption spectra of sludge composting change of its structure, and adsorption of heavy metals in sewage sludge composting mechanism of initial judgments.The infrared spectrum shows that composting the sludge containing mainly hydroxyl,amide, ether and other active groups.In the adsorption of Cd2+ after the decomposition of sludge adsorption-OH,C=O stretching vibration peak of migration.In the adsorption of Zn+ after-CH2-stretching vibration peak disappears,indicating-OH,-C=O and-CH2 groups involved in the decomposition of sludge and Zn+ adsorption reaction.