Co-reporter:Bo Xiang, Wen Fan, Xiaowei Yi, Zuohua Wang, Feng Gao, Yijiu Li, Hongbo Gu
Carbohydrate Polymers 2016 Volume 136() pp:30-37
Publication Date(Web):20 January 2016
DOI:10.1016/j.carbpol.2015.08.065
•Three types of dithiocarbamate (DTC)-modified starch derivatives were synthesized.•Adsorption mechanism was proved by chelating between DTC groups with heavy metal.•DTC-modified mesoporous starch showed superior adsorption ability for heavy metals.In this work, three types of dithiocarbamate (DTC)-modified starch derivatives including DTC starch (DTCS), DTC enzymolysis starch (DTCES) and DTC mesoporous starch (DTCMS) were developed, which showed the significant heavy metal adsorption performance. The adsorption ability of these three DTC modified starch derivatives followed the sequences: DTCMS > DTCES > DTCS. In single metal aqueous solutions, the uptake amount of heavy metal ions onto the modified starches obeyed the orders: Cu(II) > Ni(II) > Cr(VI) > Zn(II) > Pb(II). The adsorption mechanism was proved by the chelating between DTC groups and heavy metal ions through the pH effect measurements. A monolayer adsorption of Langmuir isotherm model for the adsorption of Cu(II) onto DTCMS was well fitted rather than the multilayer adsorption of Freundlich isotherm model. The adsorption kinetics of Cu(II) onto starch derivatives was found to be fit well with the pseudo-second-order model. Additionally, in the presence of EDTA, the adsorption ability and uptake amount of heavy metal ions onto these three DTC modified starch derivatives is identical with the results obtained in the absence of EDTA.
Co-reporter:Feng Gao, Hongbo Gu, Huanwen Wang, Xuefeng Wang, Bo Xiang and Zhanhu Guo
RSC Advances 2015 vol. 5(Issue 74) pp:60208-60219
Publication Date(Web):16 Jun 2015
DOI:10.1039/C5RA09761D
A novel magnetic amine-functionalized polyacrylic acid-nanomagnetite (Fe3O4-PAA-NH2) adsorbent prepared using a facile surface-initiated polymerization (SIP) method has delivered a great Cr(VI) removal performance compared to as-received Fe3O4 nanoparticles. The maximum amine group (–NH2) concentration grafted onto Fe3O4-PAA is determined to be 3.925 mg g−1 based on acid–base titrimetric analysis. The optimal pH value for Cr(VI) adsorption is around 2.0 with a Fe3O4-PAA-NH2 dose of 30 mg and contact time of 10 min at room temperature. A multilayer adsorption for the Freundlich isotherm model is well-fitted and fits better than the monolayer adsorption of the Langmuir isotherm model. The kinetics of Cr(VI) removal by the Fe3O4-PAA-NH2 nanoadsorbent is found to follow pseudo-second-order behavior with a calculated room temperature rate constant of 1.23 g mg−1 min−1 for a solution with an initial Cr(VI) concentration of 7.0 mg L−1 and pH value of 2.5. The competition adsorption tests show that the presence of other metals in polluted water, including Cu(II), Zn(II), Cd(II), K(I), Ca(II), Na(I), and Mg(II), favors the Cr(VI) adsorption by the fabricated Fe3O4-PAA-NH2 nanoadsorbent due to the affinity of the chemical potential and electronegativity of each metallic element. Moreover, the prepared Fe3O4-PAA-NH2 nanoadsorbent exhibits a good reusability and retains around 85% of its Cr(VI) adsorption capacity even after 5 cycles.
Co-reporter:Yikai Yan;Xiaowei Yi;Yijiu Li ;Qian Jia
Journal of Applied Polymer Science 2014 Volume 131( Issue 23) pp:
Publication Date(Web):
DOI:10.1002/app.41168
ABSTRACT
The interaction between two dyes (AO7 and AG25) during adsorption was studied in detail with diethylenetriamine-modified chitosan beads (CTSN-beads) as the adsorbent. Results indicate that the adsorption capacities and rates were directly related to the molecular size of the dye. The adsorption capacity and rate of AO7 could be greatly weakened by interaction with AG 25 during adsorption, which has a larger molecular size. The adsorption followed the pseudo-second-order kinetic equation and Freundlich model gave a satisfying correlation with the equilibrium data both in the single and binary component system. Adsorption could be divided into three stages, each controlled by different mechanisms. Temperature experiments showed high temperature was beneficial to the mass transfer of dyes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41168.
Co-reporter:Yikai Yan;Yijiu Li ;Qian Jia
Journal of Applied Polymer Science 2013 Volume 130( Issue 6) pp:4090-4098
Publication Date(Web):
DOI:10.1002/app.39691
ABSTRACT
This work has demonstrated that the novel chitosan derivative, synthesized by phase transition and grafting diethylenetriamine, has a great potential for the adsorption of acid dyes from aqueous solutions. Four acid dyes with different molecular sizes and structures were used to investigate the adsorption performance of diethylenetriamine-modified chitosan beads (CTSN-beads). Results indicated that the adsorption of dyes on CTSN-beads was largely dependent on the pH value and controlled by the electrostatic attraction. In addition, the adsorption rate (AO10 > AO7 > AR18 > AG25) and adsorption capacities (AO7 > AR18 > AO10 > AG25) were directly related to the molecular size of the dye and the amount of the sulfonate groups on the dye molecules. The equilibrium and kinetic data fitted well with the Langmuir–Freundlich and pseudo-second-order model. Furthermore, thermodynamic parameters indicated that the adsorption processes occurred spontaneously and higher temperature made the adsorption easier. The reuse tests indicated that the CTSN-beads can be recovered for multiple uses. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4090–4098, 2013
Co-reporter:Bo Xiang, Dong Ling, Han Lou, Hongbo Gu
Journal of Hazardous Materials (5 March 2017) Volume 325() pp:178-188
Publication Date(Web):5 March 2017
DOI:10.1016/j.jhazmat.2016.11.011
•A functionalized NiFe2O4/MnO2 nanocomposites have been synthesized via a facile hydrothermal approach.•The NiFe2O4/MnO2 nanocomposites shows the fast Pb(II) adsorption performance and high adsorption capacity.•The NiFe2O4/MnO2 nanocomposites is easily separated from the solution by an external magnet within a short period of time.•The NiFe2O4/MnO2 nanocomposites exhibits a good regeneration and reusability performance after six-cycle regenerations.A functionalized magnetic nickel ferrite/manganese dioxide (NiFe2O4/MnO2) with 3D hierarchical flower-like and core–shell structure was synthesized by a facile hydrothermal approach and applied for the removal of Pb(II) ions from aqueous solutions. Batch adsorption experiments were conducted to study the effect of solution pH, initial Pb(II) concentration, and dose of absorbents on the Pb(II) removal by NiFe2O4/MnO2. The NiFe2O4/MnO2 nanocomposites showed the fast Pb(II) adsorption performance with the maximum adsorption capacity of 85.78 mg g−1. The adsorption kinetics of Pb(II) onto NiFe2O4/MnO2 obeyed a pseudo-second-order model. The isothermal experimental results indicated that the Langmuir model was fitted better than the Freundlich model, illustrating a monolayer adsorption process for Pb(II) onto NiFe2O4/MnO2. Meanwhile, the NiFe2O4/MnO2 was easily separated from the solution by an external magnet within a short period of time and still exhibited almost 80% removal capacity after six regenerations. The NiFe2O4/MnO2 is expected to be a new promising adsorbent for heavy metal removal.The NiFe2O4/MnO2 synthesized by a simple hydrothermal method with 3D hierarchical flowerlike and core–shell structure have possessed a high removal efficiency and removal capacity of Pb(II) from aqueous water.Download high-res image (145KB)Download full-size image
