Research On Three-phase Extraction Method To Processes Waste Water Containing Heavy Metals

The heavy metal is one of water body pollution principal constituents.It is an important and urgent work to deal with the heavy metals waste water. In view of the waste water in many kinds of metallic ion's separation and the recycling question,and the predecessors'studies which have done , this article use three-phasee xtracting method to deal with the ions-Ni,Co,Cu,Fe and the high concentration ammonia nitrogen wastewater , applicating microemulsion phase todeal with the waste water.separately from the solution chemistry nature, solution thermodynamics as well as preparation coordination bond theory angle embarking,the paper carriedon the computation analysis to the waste water system and the extraction system, and used three-phase extraction methods to conduct the experimental, the result is usefull for dealing with the heavy metal waste water.The paper carried on theories calculation to lay foundation for extracting experiment. It is showed to us that the relation of remaining density and acidty in different system,and that in smaller scope 7～9 is advantageous for metals ion to extract.According to the metal ion matching things'Gibuss,it can be gotten that in thea lkale-scence scope, the matching things have the hot-unsteady easy emergence mutually abruption phenomenon.Cu owns more stability,so it should precipitate form as lordin the extract system,m atching thing separated form istime. Basis on matching key theories, it can bepredicted as that in the extracting system, the metals ion should be mainly formated mare stability, and having the color flat square matching things.In view of the three-phase extraction experiment, it is showed out thatt he main parametes, whichhave influence in them icroemulsion region,such as: concentration of extracting agent, influence of aqueous phase(O)/organic phase(A) ratio, the initial pH value of aqueous phase, the duration of oscillation and temperature were studied, withthe objective of choosing the best extraction system. The extraction and reextraction process by microemulsion consists of two stages.In the first one, the metal ion present in the aqueous phase is ex-tracted bym icroemulsion. The results of the optimization of experimental conditions are the following parameters: O/A=1:1; the concentration of nbutylamine is 50%; pH=7.5; temperature of 32.5℃; the duration of oscillation is 5min; thesettlement time above 30 min. In these conditions, the extraction yield of nickel reaches as high as 95%.In a second step, the reextraction process occurs: the microemuls ionphase, rich in metal, isacidified and the metal is recovered in a new aqueous phase, with higher concentration. In the reextraction, it isstudied that the influencese of the concentrationof HC1 and aqueous phase(O)/microemulsion phase(M) ratio.Results can be found that the reextraction yield ofnickel reaches as high as 99% when O/M=3 and HC1 =3 mol/L.After the reextraction organic may circulate the use,reduced the liquid- liquid - liquid three-phase extractcost.