Static/Dynamic Adsorption Of Thorium By Radioresistance Mangrove Endophytic Fungus Fusarium Sp.#ZZF51

Heavy metals constitute one of the largest groups of environmental pollutants inthe world and their widespread usage has caused serious hazardous problems forhuman, animals and the ecosystem. In recent decades, many scholars both at homeand abroad have conducted lots of researches into the removal of heavy metals, andthe main methods to remove the heavy metals include physical methods and chemicalmethods, which not only expensive but are also ineffectual when the metalconcentration in the water is less than100mg L-1. Therefore, the above methods havebeen restricted in application. Biosorption is famous for the advantages of low cost,high selectivity, short operation time and no by-products, so it has been seen as apotential technology to remove toxic heavy metals from industrial waters now.In this study, mangrove endophytic fungus Fusarium sp.#ZZF51was collectedfrom Chinese Zhanjiang sea area, and used to as the biosorbent to remove of thorium(Ⅳ) ions in waste water. It was including three sections that non-living fungusbiomass, living fungus biomass and citric acid treated fungus biomass. It also has areference and guidance impact on bioremediation of heavy metals pollution. At thesame time, the effects of solution pH, contact time, adsorbent concentration and initialmetal concentration on thorium(Ⅳ) adsorptionare investigated in detail. Furthervarious kinetics and equilibrium models are also applied to understand the uptakeprocess. Its main contents and results are as follows:In the first chapter, the thorium(Ⅳ) wastewater related knowledge, researchsignificance， basic contents and knowledge of the biological adsorption wereintroduced in brief.In the second chapter, adsorption of thorium(IV) from aqueous solution bynon-living biomass of mangrove endophytic fungus Fusarium sp.#ZZF51, the results show that thorium(IV) ions biosorption process was optimized at pH3.0, equilibriumtime60min, initial thorium(Ⅳ) concentration50mg L-1and adsorbent dose4.0g L-1with90.85%of removal efficiency and11.356mg g-1of adsorption capacity. Kineticsdata follow the pseudo-second-order model and equilibrium data agree with theTemkin isotherm model very well. FT-IR analysis indicates that hydroxyl andcarbonyl groups play an important role in the biosorption process.In the third chapter, study on thorium(Ⅳ) adsorption from aqueous solution byliving biomass of marine-derived fungus Fusarium sp.#ZZF51. The optimizedconditions for thorium(Ⅳ) onto the tested fungus are at pH5.0, equilibrium time8h,thorium(Ⅳ) initial concentration50mg L-1and living biomass dosage3.0g in50mLsolution with6.96mg g-1of sorption capacity and79.24%of removal efficiency,respectively. By linear fitting with many known equilibrium characteristic and kineticpatterns, the experimental equilibrium data follow the Temkin isotherm model andkinetics data agree with the pseudo-second-order model very well. SEM experimentshows the tested sample can provide ready access and rich surface area for thorium(Ⅳ)onto the binding sites. FTIR analysis indicates that hydroxyl, amino, and carbonylgroups play an important role in the biosorption process.In the fourth chapter, thorium(Ⅳ) removal from aqueous medium by citric acidtreated mangrove endophytic fungus Fusarium sp.#ZZF51. The biosorption processwas optimized at pH4.5, equilibrium time90min, initial thorium(Ⅳ) concentration50mg L-1and adsorbent dose0.6g L-1with90.87%of removal efficiency and75.47mg g-1of adsorption capacity, which is obviously greater than that (11.35mg g-1) ofthe untreated fungus Fussarium sp.#ZZF51for thorium(Ⅳ) biosorption underthecondition of optimization. The experimental data are analyzed by using isotherm andkinetic models. Kinetic data follow the pseudo-second-order model and equilibriumdata agree very well with the Langmuir model. In addition, FTIR analysis indicatesthat hydroxyl, amino, and carbonyl groups act as the important roles in the adsorptionprocess.In the fifth chapter, the adsorption result that no-living、living、citric acid treatedmangrove endophytic fungus Fusarium sp.#ZZF51was compated. In the sixth chapter, the results were summarized. Besides further studyproposals were put forward.