| It is a kind of green and efficient method that recovery metal ions by biomass adsorption from dilute solution, biological adsorption method for biomass adsorbent. It has the properties of wide raw material sources, various kinds, low cost biocompatible, synthesis of adsorbent non-toxic harmless and easily biodegradable. More importantly biomass adsorbent containing rich in active functional groups such as carboxyl, amino, hydroxyl, can complexation metal ions also facilitate further modification of adsorbent are expected to be complementary or alternative to traditional adsorption material. Orange peel, Chinese mitten crab crab shells and cornstalk were used as raw materials to prerare different characteristics of adsorbents. After a simple chemical process modification extraction of effective components,fto improve the stability of the biomass adsorbent, adsorption capacity and separation selectivity, develop the applied basic research of recycling and the separation of metal ions in the solution using biological adsorption method. Further enrich the research of biosorption mechanism and the basic theory of metal ions. The specified studies were as follows:First of all, the orange peel was prepared as raw material, which was passed with saponification treatment. Get a series of orange peel adsorbent, denoted by SOWs Fe(III)-SOW. Through the contrast of rare earth metal ions adsorption capacity of erbium, SOW has the strongest adsorption capacity, The amount of Sc3+, Nd3+, Gd3+, Er3+ adsorbed on the SOW reached approximately 46.06 mg/g,120.12 mg/g,121.33 mg/g,136.51 mg/g in case of pH 5. Using FTIR, N2 adsorption, and SEM characterized adsorbent, prove adsorbent was synthesized successfully. The thermodynamics of the adsorption of REEs were well fit with the Langmuir adsorption isotherm model. Biosorption kinetics data were successfully fit with pseudo-second-order model. By FTIR and XPS judging the adsorption mechanism of SOW adsorb rare earth metal ions erbium is cation exchange.Secondly, Chinese mitten crab (Eriocheir sinesis) as raw material, the crab chitosan CS was prepared from the simple process, abbreviated CS. After different amino acid modification made a series of amino acid modified chitosan adsorbent. The cycle effect of amino acid modified chitosan adsorbent is better, adsorbent is stable. In addition, Glu-CS was studied in rare earth metal ions adsorption capacity, maximum saturated adsorption capacity and adsorption mechanism. The maximum saturated adsorption capacity of Glu-CS adsorb Sc(III), Nd(III), Gd(III), Er(III) were 23.70 mg/g,37.33 mg/g,36.64 mg/g,35.09 mg/g respectively.Thirdly, in order to further improve the adsorption quantity, a wide range of sources of corn stover were used as raw materials, after simply acid acidification treatment denoted by OCS. And then grafting the phosphate group on OCS, adsorbent denoted by P-OCS. The maximum saturated adsorption capacity of P-OCS adsorb Sc(III), Nd(III), Gd(III), Er(III) were 27.24 mg/g.85.26 mg/g,88 mg/g.76.82 mg/g respectively. The thermodynamics of the adsorption of REEs were well fit with the Langmuir adsorption isotherm model. For the mixed rare earth metal ion selective adsorption of scandium. Adsorbent stability is good, and after three adsorption-desorption recovery basically remain unchanged. By FTIR and XPS judging the adsorption mechanism of P-OCS adsorb rare earth metal ions erbium is cation exchange. |
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