| Powdery bentonite is a kind of novel adsorbent developed in recent years. It is widely applied in the field of wastewater treatment for its better adsorption performances, ion exchange properties, abundant resources and cheap prices. In this paper, bentonite granules were prepared to resolve problems produced by powdery adsorbent, such as poor permeability, high turbidity and difficult to subside. And in order to improve the decoloration capacity, granular adsorbents were modified by chemical methods and its decoloration performances were studied onto dyes.As raw material, bentonite granules were prepared mixed with pore-causing agent and crossing-linking agent in this experiment. Then they were modified to improve the discoloring properties onto dyes in wastewater. The experiment was divided into three parts:1. By using coal as pore-causing agent and amylum as crossing-linking agen, a series of porous-organo bentonite granules were prepared. And raw samples were modified by EPI-DMA to obtain optimum properties of adsorption. The decoloration effects of this new cationic polymer bentonite granule for two types dyes-activated dyes and disperse dyes were investigated. The adsorption thermodynamic characteristics and mechanism of dyes on bentonite granules were studied by using the bottle-point technique. The influencing factors of pH value, dosage of decolorizer and reaction time were considered on the dyes removal.The results showed that porous-organo bentonite granule was obtained with the quality ratio of bentonite, coal and starch was 50:10:1 and calcined at 600℃for 6 hours. And modified bentonite granules with better adsorption capability were manufactured by reacting with the EPI-DMA concentration of 50g/L at 40℃for 4 hours. The removal rate to Reactive Turquoise Blue K-GL could be 96.78%. In the acidic and neutral conditions, the modified bentonite granule had almost the same removal effects onto dyes and strong durability, while it was greatly influenced in alkaline condition. At room temperatures, modified bentonite granules had remarkable adsorption efficiencies to different dyes. The decoloring property of modified bentonite granule to the two types of dyes was more excellent than the raw material, which were all enhanced from less than 10% up to more than 90%. The sample dosing amounts to dyes of Reactive Turquoise Blue, Reactive Brilliant Red, Disperse Yellow Brown and Disperse Blue were respectively 10g/L, 20g/L, 16 g/L and 16g/L, while the adsorption time for reactive dyes was 2h and lh for disperse dyes. The adsorption isotherm accorded with the Langmuir equation better than Freundlich equation. The adsorption dynamics followed the law of the second order kinetic equation. The order of adsorption quantity size was Disperse Blue> Disperse Yellow Brown>Reactive Turquoise Blue> Reactive Brilliant Red and the adsorption rate was Disperse Yellow Brown> Disperse Blue> Reactive Brilliant Red> Reactive Turquoise Blue.2. Taking sludge as pore-forming agent, the optimized conditions for the preparation and acidification of bentonite granules were studied. The effects of calcination temperature, roasting time and sludge content on the holes of granules were investigated to obtain porous samples with better mechanical strength. By altering acid type, acid concentration, solid-liquid ratio, activation temperature and activation time, acid activated bentonite granule with better decoloration properties was achieved. The new acidified sludge-bentonite granule was applied to the decoloration of Reactive Turquoise Blue. The influences of pH value, dosage of decolorizer, reaction time and reaction temperature were investigated onto the removal effects. The data were analyzed to fit simulated equations and the important thermodynamics parameters (ΔH~0,ΔS~0,ΔG) and the activation energy E_a were also acquired by experiment data processing.The results indicated that the optimal conditions to obtain porous sludge-bentonite granules were as follows: the calcinations temperature was 700℃, the ignition time was 7h, and the mixture ratio of sludge to bentonite was 1:3. And a product with better adsorption was acidized by the sulphuric acid of 6 moL/L with solid-liquid ratio of 1:25 (g:mL), reacting for 4h at ambient temperature. The decolorizing performance of the prepared bentonite granule, increased to 47%, was more excellent than that of the other three granular absorbents (irregular carbons, cylindrical carbons and raw materials). The discoloration results onto Reactive Turquoise Blue showed that the adsorption isotherm fitted the isothermal adsorption equation of Langmuir better than Freundlich. The adsorption dynamics followed the law of the pseudo-second order kinetic equation. The low value of E_a which was 5.52kJ/moL suggested that physical adsorption is primary. And the relation ofΔH~0>TΔS~0 mean that the influence of the enthalpy was more remarkable than the entropy in the activation reaction, whileΔG>0 also mean the chemical reactions were not spontaneous.3. Characterizing Bentonite Granules: The pore distribution of bentonite granules was analyzed through the adsorption isotherms for nitrogen. The surface structure and morphology were characterized with the help of SEM photos. The mechanical strength was measured by lost rations and the content of organic compounds was determined by the value of incandesce reduction.
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