Experimental Research On Sludge-derived Adsorbent Adsorbing Chromium

With the constant increase in the rate of sewage treatment, sewage treatmentplant sewage load also has been increasing, although the water environment can beimproved, but the resulting sewage sludge treatment and disposal more difficultproblem is more obvious. Grasp a good reasonable disposal of the sludge, theminimum requirements for sludge treatment is to achieve the reduction, sound, andto prevent the occurrence of secondary pollution.Resources of the sludge, turningwaste into wealth, been pursuing the goal.In recent years, chromium pollution incidents occur frequently, resulted insignificant personal injury and economic loss. We should linke sludge disposal andwastewater treatment containing chromium together,and dry sludge activation wasprepared adsorbent containing chromate sewage processing.Sludge Utilization atthe same time, bringing low-cost treatment of wastewater containing chromium hasa positive long-term significance.This paper first discusses the chromate sewage sludge adsorbent preparation,pickling activation of the adsorbent surface was positively charged. Parametercontrol as follows: heating rate30°C/min; Final pyrolysis temperature650°C;holding time of30min. The iodine value of the median of the adsorbent obtained159.7-176.3mg/g, methylene blue adsorption value of the median for the57.1-62.7mg/g. Isoelectric point IEP value median is4.06; median total acid group content is3.124mmol/g, the carboxyl content of the median is2.571mmol/g; phenolichydroxyl group content of the median is0.324mmol/g, insideester content in themedian is1.022mmol/g.Then, I study the effect of adsorbent and removal chromium, mainly studyingchromium adsorption removal efficiency factors: the initial concentration,adsorbent dosage, initial solution pH value, contact time, determining to removechromateexcellent condition parameters. The removal efficiency improves with theincreasing dosage and removal the balance of time is6h, optimum pH for Cr (Ⅵ)removal is2. Detection solution of hexavalent chromium and total chromiumcontent, the comparative analysis of the obtained sludge adsorbent is adsorption ofCr (Ⅵ) removal mechanism-reduction.Then, I study the adsorption kinetics, finding that adsorption removal processwith quasi-second order kinetic model is better. Through the study of adsorptioncontrol the rate of high chromium concentration, the proliferation of the maincontrolling factor. Adsorption isotherms, the Langmuir model has better fit. Finally, I select the typical organics, bovine serum albumin, soluble starch,mixed oil and humic acid, exploring the impact of its effect on sludge adsorbent toremove chromium. Affecting the removal of Cr (Ⅵ) the order is HA> mixed grease>soluble starch> of BSA.The right amount of organic matter are good to restore theion and Cr (Ⅵ) removal. Meanwhile, the smaller molecular weight and spatialconfiguration of small organic will be competitive adsorption of the effectiveadsorption point, reducing sludge adsorbent for removal total chromium.In general,organic compounds weaken the the poisoned strength of chromium-containingwastewater and will be better for Cr (Ⅵ) removal.