Effect of alkali leaching and sludge strengthening on phosphorus removal of steel slag ceramics
In order to improve the phosphorus removal effect of steel slag,alkali leaching pretreatment was used and residual sludge was added to strengthen the preparation of alkali leaching slag-montmoril-lonite-sludge composite steel slag ceramic particles.The phosphorus removal performance and mechan-ism of enhanced steel slag ceramic particles were discussed,and the removal of phosphorus-containing wastewater was investigated.The results showed that the maximum phosphorus removal rate of the two kinds of steel slag ceramics could reach 93％.When the phosphate concentration was 1 mg/L,the op-timal dosage of alkali impregnation-sludge enhanced steel slag ceramics was 0.5 g,which was signific-antly lower than that of unstrengthened steel slag ceramics(1 g).Scanning.electron microscopy(SEM)analysis showed that the pores of alkali impregnation-sludge enhanced steel slag ceramics were denser.X-ray diffraction(XRD)characterization showed that the two ceramics contained a variety of metal salts,which could be removed by reacting with phosphate ions in the water samples.The two kinds of ceramics have the highest fitting degree to Langmuir adsorption isothermal equation,and the maximum adsorption capacity of alkali impregnated sludge strengthened steel slag ceramics is higher than that of unstrengthened steel slag ceramics(Qmax:39.18＞19.18 mg).The fit degree of the two models is higher than that of the quasi-first order kinetic model,which indicates that the adsorption of phosphorus by the two kinds of ceramics belongs to monolayer adsorption and is mainly chemisorption.
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