Papers by Keyword: Zn(II)

Abstract: The adsorption behavior of Zn (II) by attapulgite were studied in the paper, The effects of adsorbent dose. Contact time, ionic strength and temperature on the adsorption were investigated. The maximum adsorption capacity is 4.129 mg.g^-1 at 333 K. The kinetic study indicated that the adsorption was a pseudo-second-order process. The adsorption was well fitted by the Langmuir adsorption isotherm model. The results indicated that the sorption of Zn (II) by attapulgite was a spontaneous process, and the sorption was endothermic.

Abstract: The amine aldehydes resin-mesoporous materials complex AFC-SBA-15 was synthesized using ordered mesoporous materials SBA-15 as the carrier. The obtained compound was characterized by FT-IR,N₂ adsorption-desorption and scanning electron microscopy. The compound retained ordered mesoporous structure and the resin polymer coated inside channels and outside surface hole wall. The adsorption behavior was carried out with the presence of EDTA in binary components of Pb (II) and Zn (II). The result showed that with the presence of EDTA, tunable selectivity could be realized.

Abstract: Co-sorption characteristics of Zn(II) and As(V) on the mixed Fe/Al-PILCs was investigated in a batch system at room temperature. The effects of relevant parameters, such as pH value of solution, adsorbent dosage, initial Zn(II) and As(V) concentrations and contact time were examined, respectively. The results show that co-sorption capacities and co-sorption rates of Zn(II) and As(V) by Fe/Al-PILC are higher and faster than those of single Zn(II) or single As(V) by Fe/Al-PILC. Co-sorption isotherm data of Zn(II) and As(V) by Fe-Al-PILC were fitted well to Langmuir isotherm and the maximum sorption capacities of Zn(II) and As(V) on mixed Fe-Al-PILCs (Q0) are 16.98 mg/g and 16.29 mg/g, respectively, which are higher than those in single system. n>1 from Freundlich isotherm indicate that the sorption of Zn(II) and As(V) by Fe-Al-PILC is favorable. E values from D-R model indicate that the type of sorption of Zn(II) and As(V) by Fe-Al-PILC is physical. The results indicate that there is significant potential for Fe/Al-PILCs as an adsorbent material for Zn(II) and As(V) removal from aqueous solutions.

Abstract: In this paper, adsorption performance of Zn(II) in simulative waste water by kaolin was studied, and the influences of solution initial pH value, temperature, adsorption time, concentration of Zn(II) were tested. Moreover, the thermodynamic parameters and kinetic equation were calculated. The results show that Zn(II) adsorption capacity firstly increases and then decreases as the pH increases, and the higher temperature, the better adsorption capacity. The Zn(II) adsorption occurs mainly within 60 minutes, and then leveling off. The calculations show that linear correlation coefficient (R2) of langmuir equation is better than the freundlich model fitting results, and Zn(II) adsorption can occur spontaneously, is an endothermic and entropy increasing process. In addition, first-order kinetic equation is more suitable for the description of Zn(II) adsorption mechanism, and adsorption activation energy equals 21.51 kJ•mol^-1.

Abstract: The complex of ZnL2Cl4 was synthesized by using zinc chloride hydrate and ligand 2-[(4-Methylpiperazin-1-yl)iminomethyl]phenol(L) under reflux conditions and anhydrous ethanol as solvent. The complex was characterized by elemental analysis, Infrared spectroscopy, solid fluorescence. Experimental results showed that the free ligand was thermally stable, and emitted intensive blue fluorescence at the peak wavelength of 493 nm. Compared with the fluorescent emission of free ligand, the complex of ZnL2Cl4 is blue-shifted to 448 nm in solid-state and exhibiting stronger blue fluorescence.

Abstract: With synthetic wastewater, a comparative study on co-sorption of Zn(II) and As(V) by Fe/Al-PILCs prepared at different calcination temperatures was investigated using a lab-scale batch experiment technique. The effects of relevant parameters, such as pH value of solution, adsorbent dosage and contact time were examined, respectively. The results show that sorption efficiencies of Zn(II) and As(V) by Fe/Al-PILC prepared at calcination temperatures of 300 °C are higher than those at 350 and 400 °C and the higher calcination temperature is, the lower sorption efficiencies of Zn(II) and As(V) are. Co-sorption isotherm data of Zn(II) and As(V) by Fe/Al-PILCs were fitted well to Langmuir isotherm and the maximum sorption capacities of Zn(II) and As(V) on Fe/Al-PILC (Q₀) prepared at 300 °C are 13.95 and 15.87 mg/g, respectively, which are higher than those at calcination temperatures of 350 °C and 400 °C. The maximum sorption capacity of As(V) decreases more obviously with increasing calcination temperature than Zn(II) does. n>1 from Freundlich isotherm indicate that the sorption of Zn(II) and As(V) by Fe/Al-PILCs is favorable. E values from D-R model indicate that the type of sorption of Zn(II) and As(V) by Fe/Al-PILCs is physical. There is significant potential for Fe/Al-PILC prepared at calcination temperature of 300 °C as an adsorbent material for Zn(II) and As(V) removal from aqueous solutions.

Abstract: Thiol-functionalized MCM-48 (SH-MCM-48) was synthesized by co-condensation method, with co-templates of cetyltrimethylammonium bromide (CTAB) and nonionic poly (ethylene oxide)–poly (propylene oxide)–poly (ethylene oxide) triblock copolymer (Pluronic P123). The resulting material was characterized by XRD and FT-IR spectrum. The potential of SH-MCM-48 for adsorption Zn (II) from aqueous solution was examined. Batch adsorption studies were carried out to investigate the effect of experimental parameters including pH, metal ions concentration and adsorption time. The maximum adsorption capacities of Zn (II) onto SH-MCM-48 were 30.12, 34.01 and 38.02 mg g^-1 at the temperature of 303, 313 and 323K, respectively. The adsorption kinetics data were found to follow the pseudo-second-order kinetic model, and adsorption isotherms were fitted well with Langmuir and Freundlich models. Moreover, the adsorption thermodynamic parameters (△G⁰, △H⁰ and △S⁰) were measured, and indicated that the adsorption was an exothermic and spontaneous process.

Abstract: The performance of expanding rice husk (ERH) fixed bed column in removing Zn (II) from aqueous solution were studied in this work. Different column design parameters like bed height, flow rate and initial concentration were calculated. It was found that ERH was found to be an effective adsorbent for removal of Zn (II); and when conducted with Zn (II) concentration 12.8 mg L^-1 and flow rate 10 ml min^-1 with different bed depths such as 3, 6 and 9 cm, the equilibrium uptake was decreased from 5.181 to 4.33 mg g^-1; the equilibrium uptake also decreased from 4.51 to 3.807 mg g^-1 with increasing of flow rate from 5 to 15 ml min^-1 and increased from 4.447 to 5.752 mg g^-1 when initial concentration increased from 12.8 to 35 mg L^-1. The dynamics of adsorption process was modeled by bed depth service time (BDST), and indicating the validity of BDST model when applied to the continuous column studies.

Abstract: A fixed bed of raw rice husk was used for the removal of Zn (II) from aqueous solution. The material as adopted was found to be an efficient media for the removal of Zn (II) in continuous mode using fixed bed column. Different column design parameters like depth of exchange zone, flow rate and initial concentration were calculated. When conducted with Zn (II) concentration 10 mg.L^-1 and flow rate 10 ml.min^-1 with different bed depths such as 3, 6 and 9 cm, the equilibrium uptake was 3.366, 2.847 and 2.764 mg.g^-1, respectively. The equilibrium uptake decreased from 2.802 to 1.975 mg.g^-1 with increasing of flow rate from 5 to 15 mL.min^-1 and increased from 2.764 to 3.798 mg.g^-1 when initial concentration increased from 10 to 30 mg.L^-1. The dynamics of adsorption process was modeled by bed depth service time (BDST), and indicating the validity of BDST model when applied to the continuous column studies.

Abstract: Removal of Zn (II) from aqueous solution by copolymer of grafting acrylic acid onto deacetylated konjac glucomannan (GADKGM) was evaluated in a bath adsorption system. Operational parameters such as pH, time, temperature and initial concentration were studied in present work. The adsorption process was relatively fast and highly effective. Removal efficiency for Zn(II) solution at the concentration of 100 mg/L was 98% at optimum operational pH of 6. The removal rate for Zn(II) on GADKGM was very fast and the removal efficiency can attain about 90% within 5 min. Isotherm adsorption data were described by Langmuir model with monolayer adsorption capacity of 125 mg/g. The negative values of thermodynamic parameters of △Go and △So indicated that adsorption process was a spontaneous process and randomness at the solid/liquid interface was decreased during the adsorption process.