| Because of its good physical and chemical properties,Nickel is widely used in chemical industry.At the same time,a lot of wastewater containing Ni2+ occured,which not only caused the waste of resources but also polluted ecological environment.The current treatment methods to wastewater containing Ni2+ include physical methods,chemical methods,physical-chemical methodsand biological methods.Among them, ion exchange treatment technology,a kind of physical-chemical methods,has a good application prospect which results from its advantages of non-toxic,pollution-freeand the reuse of nickel resources and wastewater.Ion exchange fiber(IEF) is a new kind of fibrous adsorption-separation materials,including acid,alkali and chelating active sites.Because it has the atoms(N, P, O, S) with lone pair electrons which can ligand with metal ions to form stable structure,chelating fibershas the high adsorption selectivity and could be used to treatmetal ion wastewater.In recent years,chelating fibers with its unique advantages is widely used in metal wastewater treatment fields.In this paper,a kind of PP-St-DVB imine diacetate fiber used as adsorbent processed model wastewater containing Ni2+,Ca2+ and Mg2+. The adsorption properties weresystematically studied and the adsorption desulfurization performance of the used fiberwas preliminarily studied.The specific work were as follows:(1)Laboratory-made PP-St-DVB imine diacetate fiber used as adsorbent processed model wastewater prepared in laboratory.The effects of fiber type,p H,initial concentration and temperature on adsorption performance were systematically studied.Simulating the actualwastewater treatment process,adsorption performance under column conditions were studied. The results showed that: Na-type iminodiacetic acid imide fiber had a better adsorption performance than H-type;when the p H of the solution containing Ni2+ at about 5,equilibrium adsorption capacity was up to the maximum(97.45 mg/g);the bigger the initial concentration of the solution was,the better the adsorption was and the adsorption accorded to pseudo-second order kinetic model;the higher the temperature was,the better the adsorption was and Langmuir adsorption model could better describe iminodiacetic acid fiber adsorption process for Ni2+,indicating that the adsorption process was endothermic monolayer chemically adsorbed;under column conditions,iminodiacetic acid fiber had good adsorption performance for Ni2+ and the adsorption capacity was 92.14 mg/g which was similar to the theoretical adsorption capacity(102.7~132.1 mg/g).(2)The adsorption selectivity of iminodiacetic acid fiber for Ni2+ in Ca2+,Mg2+ coexist simulated wastewaterwas mainly studied.The results showed that:the adsorption selectivity order was Ni2+> Ca2+> Mg2+and the selectivity coefficients increased with extension of adsorption time;under the column conditions,the selectivity coefficients of kC N and kM N were respectively up to 5.26 and 136.2 which were significantly higher than the selectivitycoefficients of static conditions;the high adsorptive selectivity for Ni2+ of iminodiacetic acid fiber had an important significance for the enrichment and purification of nickel resources.(3)Hydrochloric acid and sulfuric acid were respectively used as the eluent to examine elution regeneration performance of iminodiacetic acid fiber for Ni2+.The results showed that: when 2.5 mol/L sulfuric acid were used as the eluent,adsorption capacity of iminodiacetic acid fiber for Ni2+ was essentially the same and the elution rate of Ni2+ were all over 94% by five times adsorption-elution regeneration cycles.So the fiber was expected to apply to the actual recovery of nickel resources and purification of nickel wastewater.(4)Desulfurization performance for simulate gasoline of iminodiacetic acid fiber adsorbed Ni2+was examined and several other transition metal-containing fibers were developed to be used in desulfurization for simulate gasoline and then they were contrasted.The results showed that:in the low sulfur content(200 mg/L) and low oil ratio conditions iminodiacetic acid fiber adsorbed Ni2+, N-methylimidazole PPS fibers and amidoxime chelate PAN fibers respectively liganded with Cu Cl, Fe Cl3 and Zn Cl2 showed good adsorption desulfurization effect.The adsorption amount of sulfur was 1.2-5.2 mg/g.The maximumdesulfurization rate was up to 29.2%.Among them the minodiacetic acid fiber siaturated with Ni2+had the highest desulfurization rate, indicating that iminodiacetic acid fibers was a kind of excellent adsorbent which could be orderly used in wastewater containing Ni2+ treatment and gasoline desulfurization. |
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