| Along with the rapid development of China’s economic, urbanconstruction, industrial and agricultural production and other human activitiesemit large quantities of heavy metals into the environment in the process ofdevelopment, causing serious environmental pollution problems. It’s noteasily decomposited when the heavy metal pollutants release into theenvironment medium, at the same time, participate in the food chain cycle,bioaccumulate and amplify through the biological accumulation effect, threatthe human being’s health seriously.Functional groups can be selected into magnetic nanoparticles bychemical modification process and formated the magnetic functionalcomposites with adsorption performance and magnetic separation performance, low cost, easy operation, it has received attention in solving theheavy metal pollution problems effectively.This work developed the magnetic functional composites usingxanthan gum, sodium alginate natural polysaccharide to adsorb and recoverheavy metals pollutants in water based on the previous work.Thebreakthrough work was focus on the following parts:(1) The optimization of Fe3O4@SiO2-xanthan gum composites’preparation conditions and its adsorption behavior research for Pb2+, Cu2+,Zn2+, Cd2+heavy metal ion: the the four kinds of metal ions’ dsorption onFe3O4@SiO2-XG composites fitted to the Langmuir adsorption isotherm, themaximum saturated adsorption capacity for Pb2+, Cu2+, Zn2+and Cd2+were21.32mg·g-1、6.42mg·g1、3.89mg·g1and2.82mg·g1, respectively, themaximum adsorption capacity clearly followed the order as Pb2+>Cu2+>Cd2+> Zn2+. Adsorption thermodynamics research showed that the adsorptionprocess was spontaneous endothermic reaction. The results of the effect ofsalt ions and coexist ion on the adsorption showed that the adsorption effectof Pb2+on Fe3O4@SiO2-XG composites decreased gradually along with theincrease of the ionic strength and different kind of salt ions had various effecton Pb2+removal following the order as CaCl2>MgCl2>KCl>NaCl. When theconcentrations of co-existing metal ions were0.5mg·L-1-2.0mg·L-1, it had no obvious influence on the Pb2+removal using Fe3O4@SiO2-XG compositeas adsorbent with the metal ions Cu2+, Zn2+, and Cd2+present in aqueoussolution.(2) The adsorption and recovery of lead ion in actual industrialwastewater by Fe3O4@SiO2-xanthan gum composites: the Pb2+adsorbed onFe3O4@SiO2-XG composite could be desorbed effectively by0.1mol·L-1HCl, the composites still had good adsorption and desorption effect after thecorresponding21times adsorption-stripping process. The composites used forlead-acid battery factory, and other industrial wastewater containing Pb2+, andachiened water purification and target metal recycling.(3) Fe3O4@SiO2-xanthan gum composite combined with atomicspectrometry used to enrich, separate and analysize heavy metal ion in watersamples. When used for the actual seawater’s adsorption-desorption, it couldremove the large amounts of salt to eliminate the interference to lead testwhich combined with matrix improver to analyze the target lead ion, RSD isless than8%, the measured recovery of east sea water standard sample ismore than90%.(4) Magnetic sodium alginate composites were used for enrichmentand separation of As(V), the amount of magnetic Fe3O4joined into magneticsodium alginate composites had effect on enrichment of As (Ⅴ). When the amount of magnetic Fe3O4was2g, the dose of magnetic sodium alginatecomposites were2g, reaction time was30min, pH was4, it could meetenrichment and separation effect. |
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