The Study Of Zr(Ⅳ)-based Metal-Organic Frameworks Adsorption Removal Of As & Sb From Contaminated Water And Detection Of Hg

Mercury, arsenic and antimony pollution had become a serious issue for many years. Therefore, detecting and removing these heavy metal ions from water were very important to protect the human health and environment. In this study, we developed a new method to detect the Hg2+in the water samples, we also developed Zr-benzenedicarboxylate and its derivative for exceptional removal of arsenic(III, V)and antimony(III, V) from contaminated water.We developed a sensor which showed highly selective for Hg2+in present of other metal ions. In this study, the quantum dots(Cd1-x ZnxSe1-y Sy core-shell QDs)acted as the energy donor and the GO acted as the energy acceptor. When Hg2+was present in the sample solution, the single strand DNA functioned on the quantum dots and GO will hybridize. ssDNA hybridization occurs because Hg(II) can stabilize thymine- thymine(T-T) mismatch hybridization through the thymine-Hg2+-thymine(T-Hg2+-T) complexes in oligonucleotide, subsequently, the quantum dots and GO are brought into the close proximity, which made the nanometal surface energy transfer(NSET) from the QDs to the GO. This study showed that the biosensor had promising potential for detection of mercury(II). Under the optimum conditions, this nanosensor exhibited a limit of detection of 0.1 and 0.2 μg?L-1 toward Hg(II) in the buffer solution and in the river water, respectively.Zr(IV)-Based Metal-Organic Frameworks(MOFs): Zr-benzenedicarboxylate(UiO-66) and its derivative(UiO-66(NH2)) were successfully prepared via a facile solvothermal method and applied to remove As(III) and As(V) from an aqueous solution. UiO-66 had an exceptional As(III) and As(V) removal capacities of 200.16 and 73.15 mg/g, respectively. The thermodynamic experiment results demonstrated that the adsorption processes were all the exothermic reaction. The adsorption process between arsenic and UiO-66 & UiO-66(NH2) was identified to chemical adsorption after the calculation of the Dubinin-Radushkevich(D-R) isotherm model and pseudo-second-order kinetic model. UiO-66 demonstrated a more excellent arsenic removal performance on both As(III) and As(V), and had been applied to commonly used fixed-bed adsorption reactors in the industry. The initial arsenic concentration was 100 ppb, the UiO-66 reached 2270 BVs and 1775 BVs for the As(III) and As(V),respectively, until the regulation level of 10 ppb for drinking water after adsorption in the water treatment reached. An X-ray photoelectron spectroscopy(XPS) indicated that the bond of Zr-O was formed with As(III) and As(V) as it shifted to lower values after As(III) and As(V) adsorption.UiO-66 and UiO-66(NH2) also had been successfully applied to remove of the Sb(III) and Sb(V) from an aqueous solution. UiO-66(NH2) had a better performance with Sb(III) and Sb(V) removal capacities of 61.8 and 105.4 mg/g, respectively.UiO-66 had an exceptional Sb(III) and Sb(V) removal capacities of 53.5 and 99.5mg/g, respectively. The thermodynamic experiment results demonstrated that the adsorption processes were all the endothermic reaction. The Dubinin-Radushkevich(D-R) isotherm model and the pseudo second-order kinetic demonstrated the adsorption process between Sb and UiO-66(NH2) was chemical adsorption.It demonstrated UiO-66 and its derivatives(UiO-66(NH2)) may have a promising potential for their application in water treatment practice for they are non-toxic,highly stable, and resistant to acid and alkali, high arsenic and antimony adsorption capacity and also could easily adapted for various arsenic and antimony removal apparatus.