Shaoming Yu

Adsorption of phenol and 1-naphthol onto XC-72 carbon

XC-72 carbon (XC-72) was characterized by SEM, XPS, N2 adsorption-desorption, particle size distribution analysis and potentiometric acid-base titration. The adsorption of phenol and 1-naphthol on XC-72 was studied as a function of contact time, pH, adsorbent content and temperature. The kinetic adsorption data were described well by the pseudo-second-order model. The adsorption isotherms of phenol were described well by Freundlich model, while the adsorption isotherms of 1-naphthol were fitted well by Langmuir model. The results demonstrated that XC-72 had much higher adsorption capacity for 1-naphthol than for phenol. The adsorption thermodynamic data were calculated from the temperature-dependent adsorption isotherms at T=293, 313 and 333 K, and the results indicated that the adsorption of phenol was an exothermic process, whereas the adsorption of 1-naphthol was an endothermic process. XC-72 is a suitable material for the preconcentration of phenol and 1-naphthol from large volumes of aqueous solutions.

Facile Synthesis and Characterization of Chrysotile Nanotubes and Their Application for Lead(II) Removal from Aqueous Solution

Chrysotile nanotubes (ChNTs) were synthesized using the hydrothermal method and characterized by XRD, XPS, SEM, TEM, and N2 adsorption-desorption. The results of XRD analysis confirm that the synthetic samples own the pure monoclinic chrysotile. The morphology images show that ChNTs have a hollow nanotubular structure. A batch experiment was employed to evaluate the adsorption efficiency of ChNTs toward Pb(II). The kinetic adsorption of Pb(II) on ChNTs can be described by a pseudo-second-order model very well. The adsorption of Pb(II) on ChNTs are strongly dependent on pH and ionic strength. The adsorption isotherms are fitted well by the Langmuir model, having a maximum adsorption capacity of 25.08 mg·g−1 at 298 ± 1 K. The thermodynamic parameters of the adsorption for Pb(II) indicate that the adsorption process of Pb(II) on ChNTs is spontaneous and endothermic. Herein, this finding suggests that ChNTs can be applied on the preconcentration of Pb(II) in the field of water treatment.

Removal of radiocobalt from aqueous solution by different sized carbon nanotubes

Batch adsorption technique was applied to study the adsorption of radiocobalt on multiwalled carbon nanotubes (CNTs) with deferent sizes. The aim of this work was to examine the effect of contact time, pH, solid content, foreign ions and CNT particle sizes on the removal of Co(II) ions from aqueous solutions by CNTs. The results indicated that the adsorption of Co(II) was strongly dependent on pH and the adsorption capacity was in inverse proportion to the particle sizes of CNTs. The adsorption of Co(II) was weakly affected by ionic strength and foreign ions. Ion exchange and surface complexation were the main adsorption mechanisms. The kinetics of Co(II) adsorption on CNTs was described well by pseudo-second-order model. The Langmuir and Freundlich models were applied to interpret the adsorption data. The results are important to understand the physicochemical behavior of Co(II) with CNTs, and for the application of CNTs in the preconcentration of radiocobalt from large volumes of aqueous solutions.

Facile synthesis of α-Fe2O3/diatomite composite for visible light assisted degradation of Rhodamine 6G in aqueous solution

Abstractα-Fe2O3 particle supported on diatomite (α-Fe2O3/diatomite composite) was prepared at room temperature by the chemical precipitation method using ferrous sulphate as the raw material and diatomite as supporter. α-Fe2O3/diatomite composite was characterized by XRD, FE-SEM, FT-IR and DRS. The result showed that α-Fe2O3 was uniformly loaded on the diatomite. The photocatalytic activity was investigated under visible light toward degradation of Rhodamine 6G aqueous solution and the effects of various experimental factors on Rhodamine 6G degradation were investigated. Compared with the α-Fe2O3, α-Fe2O3/diatomite composite had significantly enhanced activity in the degradation of Rhodamine 6G under visible light irradiation. Besides, the photostability of catalysts was also investigated. The experimental results indicated that the prepared composite is a promising material for the wastewater treatment for its good catalytic performance property and long-term stability.

In-situ synthesis of hydrotalcite and its application in separation of simulated radionuclide Eu(III)

The simulated radionuclide Eu(III) was separated effectively by using the in-situ synthesis of hydrotalcite. The optimal conditions of pH, Mg/(Eu+Al) molar ratio, and initial Eu(III) concentration for separating Eu(III) and achieving a single hydrotalcite phase were investigated systematically and determined to be 10, 3.0, and 600 mg L−1, respectively. Under the optimal separation conditions, the removal percentage of Eu(III) reached 99.8%. The characterization results suggested that Eu(III) was incorporated into the crystal lattice of hydrotalcite completely and fully immobilized in the structure of spinel by calcining, and the morphology of the synthetic hydrotalcite containing Eu(III) was in hexagonal platelet-like sheet.

Impact of environmental conditions on the removal of Ni(II) from aqueous solution to bentonite/iron oxide magnetic composites

The sorption of radionuclide 63Ni(II) on bentonite/iron oxide magnetic composites was investigated by batch technique under ambient conditions. The effect of contact time, solid content, pH, coexistent electrolyte ions, fulvic acid, and temperature on Ni(II) sorption to bentonite/iron oxide magnetic composites was examined. The results demonstrated that the sorption of Ni(II) was strongly dependent on pH and ionic strength at pH <8.0, and was independent of pH and ionic strength at high pH values. The sorption of Ni(II) was dominated by outer-sphere surface complexation or ion exchange at low pH, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The experimental data were well fitted by Langmuir model. The thermodynamic parameters (∆G°, ∆S°, ∆H°) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Ni(II) on bentonite/iron oxide magnetic composites was an endothermic and spontaneous processes. The results show that bentonite/iron oxide magnetic composites are promising magnetic materials for the preconcentration and separation of radionickel from aqueous solutions in environmental pollution.