A novel magnetic arsenate imprinted polymer (MIIP) was synthesized through a surface imprinting technique with combined utilization of two different amine containing functional monomers (allylamine and 3-aminopropyl triethoxysilane) and tetraethyl orthosilicate modified magnetic Fe3O4 nanoparticles as a support. The synthesized MIIP was used to investigate the selective adsorption performance for arsenate. The results showed that this MIIP has a high selective As (V) adsorption efficiency and easy for the separation of the adsorbent from aqueous solutions. In the presence of competing ions including Ca2+, Mg2+, Cd2+, Zn2+, Cu2+, Mn2+, Ni2+ and As (III), the synthesized MIIP can selectively and efficiently adsorb As (V) species. Compared with the non-imprinted magnetic polymer (NIP), it was found that this MIIP showed high selectivity coefficients for As (V)/Ca2+, As (V)/Mg2+, As (V)/Cd2+, As (V)/Zn2+, As (V)/Cu2+, As (V)/Mn2+, As (V)/Ni2+, and As (V)/As (III) with 4.46, 5.60, 5.45,8.48,13.5,15.9,38.7, and 102.9, respectively. Langmuir model was applied to fit the adsorption isotherm data, and the maximum adsorption capacity for As (V) was calculated as 7.53mg/g.

No abstract

The model of second-order reaction kinetics has been used to stimulate the monochloramine decay in model and distribution system waters by nonlinear fit. Several factors were investigated, including pH, bromide, nitrite concentrations in this system. The results showed that pH value was an important factor on the monochloramine decay rate, especially when pH was below 7.0. Presence of bromide ions had different impact under experimental conditions However, when pH was above 7.60, 0.1 mg/L concentration of bromide affect hardly the decay rate of mononchloramine. The results demonstrated that the second-order kinetic model could fit well the experimental results of monochloramine decay reaction under the conditions of bromide, and nitrite ion. Finally, the work presented here validates and extends this model for use in distribution systems under realistic chloramination conditions.

MnO2-loaded D301 weak basic anion exchange resin was used as adsorbent to simultaneously remove Co2+, Ni2+, Cd2+, Zn2+ andCu2+ from aqueous solution contained high concentration of alkali and alkaline-earth metals ions. The effects of solution pH and coexistent ions on the adsorption were investigated. The results indicated that Co2+, Ni2+, Cd2+, Zn2+ andCu2+ can be simultaneously removed in the wide pH range of 3 to 8. The coexistence of PO43− decreased the heavy metal ions removal rate, but for other high concentrations coexistence cations and anions such as Na+, K+, Cl−, NO3−, SO42− and HCO3−, there is no significant impact on removal rate of heavy metals. The adsorption isotherm can be well described by Langmuir isotherm. The adsorption processes followed the pseudo first-order kinetics model. High adsorption capacity makes it a good promising candidate material for simultaneous removal of Co2+, Ni2+, Cd2+, Zn2+ andCu2+ from aqueous solution with the co-existence of high concentration of alkali and alkaline-earth metals ions.

A novel Mg/Fe/Ce layered double hydroxide (LDHs) and its calcined product (CLDH) were synthesized and CLDH was used as adsorbents for the removal of chlorate ions. Results showed that the initial solution pH was an important factor influencing the chlorate adsorption. The adsorption behavior of chlorate followed the Langmuir adsorption isotherm with a maximum adsorption capacity of 18.2 mg/g. The adsorption kinetics of chlorate on CLDH can be described by the pseudo-second-order kinetic model. It was concluded that the CLDH material is a potential adsorbent for the purification of polluted water with chlorate.

In this study, 701 weak base epoxy anion-exchange resin was used as a low-cost adsorbent to remove Cr(V) from the light polluted water. To optimize its usage, the influences of pH, contact time, resin dosage and coexisting ions were investigated. Adsorption process was found to be highly pH dependent. The optimum pH range for adsorption of Cr(VI) was found to be between 6 and 8. The necessary time to reach adsorption equilibrium is about 20min. Langmuir and Freundlich adsorption isotherms were applicable to the adsorption process and their constants were evaluated. It was found that the Langmuir model yields a much better fit to the data compared with that of the Freundlich model.

No abstract

Since accurately identifying the error source which causes the exception is important, the problem of diagnosis for composite service becomes one of the key issues in the adaptive service composition. This paper proposes an approach for diagnosing composite service. In this approach, the uncertain casual relation between the exception and the service is formed by the way of computing the error propagation degree. The diagnosing algorithm which is based on the error dependent matrix is established. The diagnosis can be achieved by fuzzy reasoning. This approach can preserve the efficiency and accuracy of the diagnosis for composite service, which can support the self-adaptation of the composite service effectively.