The adsorption of Pb(II) and Cd(II) ions from aqueous solution was studied by Common Reed (CR) activated with NaOH solution of 0.5 M. CR materials obtained were characterized using XRD, SEM and FT-IR. The adsorption data were studied for adsorption isotherms of Langmuir and Freundlich models. Adsorption of Pb(II) and Cd(II) ions was best fitted with Langmuir adsorption isotherm. The maximum adsorption capacity of Pb(II) and Cd(II) ions were 19.84 mg/g and 17.33 mg/g, respectively. Experimental data were also performed to the pseudo-first-order and pseudosecond-order kinetic models. The results indicated that the biosorption of Pb(II) and Cd(II) ions on activated CR biomass followed well the second-order kinetics. The results indicated that CR can be used as a low-cost adsorbent for the removal of heavy metal ions in wastewater.
In the present study, the synthesis of ZnO/LSAC through pyrolysis of the carbonized material prepared from longan seed, zinc acetate in alkaline medium. The obtained materials was characterized by means of XRD, SEM, TEM, BET and UV-Vis-DRS. The XRD patterns of ZnO/LSAC nanocomposites were assigned to wurtzite structure of ZnO with crystallite size about 15 to 30 nm. SEM and TEM observations showed the spherical ZnO particles formed on the activated carbon. The band gap energy and specific surface area of ZnO/LSAC were found to be 2.79 eV and 294.4 m2/g, respectively. The photocatalytic activities of the prepared materials were evaluated for the degradation of Rhodamine B (RhB) dye. The removal of RhB was found to be pH dependent, and the optimized removal efficiency reached to 93.75% and the mineralization level was over 84,09% at initial RhB concentration of 40 mg.L-1 andpH 7 following 120 min under visible-light illumination. The kinetic studies showed the decolorizationof RhB followed pseudo first-order kinetics with the rate constant were determined kapp= 1.67Í10-2 min−1
Undoped and Fe-doped ZnO nanosheets have been successfully synthesized by hydrothermal method using zinc acetate as the source of Zn2+, iron(III) nitrate as the doping source, urea as media to control the solution pH and polyethylene glycol as structure-directing agents. The obtained materials were characterized by means of XRD, TEM, BET, FT-IR and UV-Vis-DRS. The results show that ZnO has a hexagonal wurtzite structure and that the Fe3+ ions were well incorporated into the ZnO nanosheets crystal lattice. As the Fe/Zn molar ratios increased from 0.05% to 0.1% results in increased absorption in the visible region of the spectrum, a slightly decreased optical band gap and increased photocatalytic activity in comparison with the undoped ZnO. The photocatalytic activity was evaluated based on photodegradation of methylene blue (MB) in aqueous solutions under visible light irradiation. The optimum Fe doping at the molar ratios of Fe/Zn = 0.1% showed the highest photocatalytic activity and was 2.19 times higher than that of undoped ZnO. The kinetic studies showed the decomposition of MB followed pseudo first-order kinetics with the rate constant were determined kapp = 7.33×10-2 min−1.
Fe-doped TiO2 nanotubes were prepared by hydrothermal method using ferric nitrate and commercial TiO2 powder. The obtained materials were characterized by means of XRD, TEM, BET, FT-IR and UV-Vis-DRS. The photocatalytic activity was evaluated based on photodegradation of methylene blue under visible light irradiation. The results show that Fe3+ ions might incorporate into the lattice of TiO2 nanotubes. Fe-doped TiO2 materials showed narrower band gap energies, higher specific surface areas, more hydroxyl groups on the surface and significantly improved photocatalytic activity. The optimum Fe doping at the molar ratios of Fe/Ti = 0.5% showed the highest photocatalytic activity and was 3.08 times higher than that of undoped TiO2. The kinetic studies showed the decomposition of MB followed pseudo first-order kinetics with the rate constant were determined kapp = 5.64×10-2 min−1.
Vật liệu N, W-TiO2/Bentonit được điều chế bằng phương pháp trộn ướt hỗn hợp bột khô N, W-TiO2 trong huyền phù bentonit, và tính chất của vật liệu được xác định bởi các phương pháp XRD,TEM và BET. Ảnh hưởng của thời gian và lượng chất xúc tác đến quá trình phân hủy quang các hợp chất hữu cơ có trong nước thải chế biến thủy sản cũng được khảo sát. Kết quả nghiên cứu cho thấy, vật liệu điều chế được có kích thước hạt khoảng 3,5 nm, diện tích bề mặt riêng khoảng 71,82 m2/g và có khả năng xử lý tốt nước thải chế biến thủy sản. Với lượng chất xúc tác 150 g/100 L nước thải và thời gian phân hủy khoảng 6 giờ thì nước thải sau quá trình xử lý đã đạt được mức A theo tiêu chuẩn kỹ thuật quốc gia về nước thải.
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