Study On Removal Of Manganese And Phenol From Water With Synthetic Manganese Oxide

With a low zero charge, a big surface area, a high negative charge, the surfactantand other characteristics, manganese oxides can be used as the absorbent, the oxidizingagent and the contacting catalyst body. The material can be adsorbed directly andoxidized by manganese oxides. Manganese oxides had the catalysis of the redox. In thisstudy, various structures and types of manganese oxides had different properties,through artificial rapid synthesis of three different kinds of manganese oxide（SMO）.SMO were studied the effect of the removal of Mn²⁺and phenol.1、Three kinds of manganese oxide（SMO） were made by artificial chemicalmethod.The colour of acidic manganese oxide was dark brown with metallic luster,thecolour of alkaline manganese oxides was glossy black with metallic luster, the colour ofoxidizing manganese oxide was red brown with metallic luster. Electron microscopyanalysis indicated that the surface of acidic manganese oxide was spherical and thewhole was three-dimensional porous layer; the surface of alkaline manganese oxide waslamellw and the whole was three-dimensional porous layer; the surface of oxidizingmanganese oxide was floc and layeredly desposited; XRD analysis showed that thethree manganese oxide crystals did not form crystals in good condition, showing nofixed shape, and the of surface synthetic manganese oxide had an OH group.Murray’sbasic reference titration of manganese oxides showed that pHpzc of acidic manganeseoxide,alkaline manganese oxide and oxidizing manganese oxide were respectively1.85,2.93,2.05.2、Langmuir equation can be used to describe manganese oxide （SMO） for Mn²⁺adsorption isotherms, indicating that the adsorption monolayer adsorption; Thesaturated adsorption capacity of the kind of SMO for Mn²⁺was approximately same.Itindicated the maximum adsorption capacity of SMO was nothing with the shape andsynthetic manner.Lagergren pseudo-second order kinetic equation can be described formanganese oxides on the adsorption kinetics of Mn²⁺,indicating that the adsorptionprocess was a chemical adsorption process and it was controlled by the diffusion step;The saturation adsorption amount of acidic manganese oxide, alkaline manganese oxideand manganese oxide was respectively86.96mg/g,79.37mg/g,90.91mg/g.3、With100mL volume and initial concentration of10mg/L of manganese solution,to achieve the maximum removal effect,the best optima dosage of acidic manganese oxide, alkaline manganese oxide and oxidating manganese oxide was respectively10、15、10mg/L; Increasing pH was helpful to adsorpt Mn²⁺for SMO; Fe²⁺in waterdisturbed the adsorption of manganese ion;When Fe²⁺concentration in water increasedfrom0mg/L to15mg/L,the adsorption amount of manganese descreased more.4、Under aerobic conditions,the adsorption amount of SMO for Mn²⁺in water wasmore than that in the absence of oxygen（filling nitrogen in exsperiment condition）.Itindicated that SMO had a catalytic oxidation for the adsorpted manganese ions.Increasing pH of the solution can promote the oxidation efficiency of Mn²⁺by SMO.5、SMO can remove phenol and was accompanied by the release of Mn²⁺. It meansthat ophenol was removed in water by oxidating using SMO.Oxidation capacity ofSMO:oxidizing manganese oxide>acid manganese oxide>alkaline-manganese oxides.The ability of oxidating phenol by SMO was decreasing with the increasing of pH. Asdosage of SMO increased,the removal rate of the oxidation of phenol rised.With theincrease of the concentration of phenol,the oxidation amount of phenol by SMOgradually increased. The coexisted metal ions had the effect on the oxidation of phenolby SMO,the degrees of inhibition:Na+<Ca²⁺≈Mg²⁺<Zn²⁺≈Cu²⁺<Ba²⁺≈Pb²⁺<Mn²⁺. Whilethe Na+, Ca²⁺, Cu²⁺coexisted, the inhibition degree was srongest for oxidation ofphenol by SMO.