Enhanced photocatalytic capacity of ZnS–ZnO–Sm2O3 composites for the removal of dyes and antibiotics in visible light region

Xiaogang Zheng,Fuyan Kang,Congying Huang,Sihao Lv,JinYang Zhang,Hao Peng 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.88 No.-

ZnS–ZnO–Sm2O3 (Zn–Sm–XY) composites were prepared via the high-temperature calcination of coreshellstructured ZnS@Sm2O3 for the enhanced photocatalytic degradation of dyes and antibiotics invisible light region. Effects of calcined temperature, Sm2O3 content, pH value, contaminantconcentration, and inorganic ions on the photocatalytic activity were investigated. Ternary Zn–Smcomposites exhibit the excellent photocatalytic activity for the visible light driven degradation oftetracycline hydrochloride. Among these composites, Zn–Sm–2B prepared via the heat-treatment ofZnS–Sm2O3 at 673 K shows the best photocatalytic activity for the removal of tetracycline hydrochloride. The enhanced photocatalytic activity of Zn–Sm–2B is also achieved for the visible light drivendegradation of methyl orange, methylene blue, and rhodamine B within 20 min. In addition, Zn–Sm–6Ccalcined from Zn–Sm–C at 1073 K as well as Zn–Sm–2B exhibits excellent photocatalytic activity. OH andO2radicals are vital for the enhanced photocatalytic activity of Zn–Sm–2B and Zn–Sm–2B in visiblelight region, respectively. The lattice defects, sulfur vacancies, and oxygen vacancies facilitate the efficientcharge transfer and the rapid separation of electron-hole pairs at the junction interface of Zn–Sm–2B.

Enhanced photo-Fenton degradation of tetracycline using TiO2-coated α-Fe2O3 core–shell heterojunction

Xiaogang Zheng,Wendi Fu,Fuyan Kang,Hao Peng,Jing Wen 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.68 No.-

TiO2-coated cubic α-Fe2O3 with mostly exposed (012) and (101) facets (α-Fe2O3@TiO2) was fabricated using a hydrothermal route for the photo-Fenton degradation of tetracycline under visible light irradiation. TiO2 coating could greatly affect the photocatalytic activity of α-Fe2O3@TiO2. Compared with cubic α-Fe2O3 alone for photodegradation of tetracycline, α-Fe2O3@TiO2 with TiO2 shell of around 15 nm exhibited higher removal efficiency of tetracycline in photo-Fenton system, and its durability was slightly affected after five cycle times under same conditions. It is ascribed to the well-matched interface between cubic α-Fe2O3 core and TiO2 shell, leading to the broadened light-absorption and the efficient separation of photo-generated electon–hole pairs. The OH radicals were main responsible for the advanced photocatalytic performance of α-Fe2O3@TiO2 in visible-light driven degradation of tetracycline.

In-situ synthesis of NiS-modified MgO/S-doped biochar for boosting the adsorption-photocatalytic activity

Xiaogang Zheng,Liping Wang,Yuanliang Zhou,Meiyin Luo,Hongyan Li,Zongyang Bo,Weixin Zheng,Chenggong Chang,Jing Wen,Jinmei Dong 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

Biochar-based composites have been intensively applied in wastewater treatment. To boost theadsorption-photocatalytic capacity of biochar for dyes elimination, S-doped biochar was commodifiedby NiS and MgO (NiS-Mg/S-BC) via the one-pot sulfurization at high temperature. The functional groupsin NiS-Mg/S-BC provided the abundant vacant sites for RhB adsorption and photocatalysis, and the junctioninterface among NiS, MgO, and S-doped biochar was likely to form the channels for the separationand transfer of photo-induced e-/h+ pairs. NiS-Mg/S-BC presented the better adsorption-photocatalyticcapacity of RhB than S-doped biochar, NiS and MgO modified biochar. Langmuir and second-order modelswell described the adsorption behaviors of NiS-Mg/S-BC. The removal efficiency of optimal 2b-NiS-Mg/SBCfor 400 mg/L RhB solution was 96.98% within 120 min, and its adsorption capacity based on secondordermodel was 802.49 mg g1. The photo-corrosion induced to the declined removal efficiency of 2b-NiS-Mg/S-BC to 94.13% after five cycles.

MgO nanosheets with N-doped carbon coating for the efficient visible-light photocatalysis

Xiaogang Zheng,Ke Wang,Zhiping Huang,Yong Liu,Jing Wen,Hao Peng 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

MgO nanosheets with N-doped carbon coating (MgO@N-C) were fabricated for the enhancedphotocatalytic degradation of dyes (methylene blue, methyl violet, and Rhodamine B) and antibiotics(ciprofloxacin and tetracycline hydrochloride) in visible light region. The effects of N-doping content,reactant concentration, pH value, and inorganic ions on the photocatalytic performance in degradation ofmethylene blue were investigated in this work. Narrow band gap energy and heterojunction interfaceendowed the extended light-harvesting capacity to visible light region and the efficient charge transfer,leading to the excellent photocatalytic activity and durability of MgO@N-C-3 with N-doping content of 1.52%.

Carbon-coated Mg–Al layered double oxide nanosheets with enhanced removal of hexavalent chromium

Xiaogang Zheng,Fuyan Kang,Xinhui Liu,Hao Peng,JinYang Zhang 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

Carbon-coated Mg–Al layered double oxide (MgAl@C LDO) nanosheets were synthesized for the removalof hexavalent chromium (Cr(VI)) ions. Carbon coating could enhance the sorption capacity of Mg5Al1 LDOfor the Cr(VI) removal. The sorption capacity of Mg5Al1@C LDO increased and then decreased with anincrease in carbon-coated content, of which the Mg5Al1@C-2 with a carbon thickness of around 5.0 nmexhibited the best sorption capacity. The sorption behaviors of Mg5Al1@C-2 was explained by Langmuirsorption model, pseudo-second-order model, Weber–Morris model, and Boyd kinetic model. Mg5Al1@C-2 for Cr(VI) removal was a spontaneous, endothermic, and chemisorption process.

Efficient solar-light photocatalytic H2 evolution of Mn0.5Cd0.5S coupling with S,N-codoped carbon

Hao Peng,Congying Huang,Xiaogang Zheng,Jing Wen 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

The low-cost and highly-efficient photocatalysts for solar-light induced water splitting had drawn greatattention to develop the renewable hydrogen economy. To enhance the solar-light driven H2 evolution ofMn0.5Cd0.5S, Mn0.5Cd0.5S was modified by S,N-codoped carbon (3-MCS/SN-C) via the in-situ sulfurizationat high temperature. In contrast with Mn0.5Cd0.5S (11.13 mmol g1 h1) and S-doped g-C3N4(0.35 mmol g1 h1), the optimal 3-MCS/SN-C with a mass ratio of Mn0.5Cd0.5S to S,N-codoped carbonof 1:3 exhibited the best H2 evolution rate of 27.58 mmol g1 h1 and an apparent quantum yield of27.43% at 400 nm. The photo-corrosion induced to the decreased H2 evolution capacity of 3-MCS/SN-Cfrom 131.13 to 126.52 mmol g1 after five cycles of 5 h. S,N-codoped carbon could efficiently capture visiblelight and absorb the photons, leading to the efficient transformation and separation of photogeneratedcarriers at the junction interface between Mn0.5Cd0.5S and S,N-codoped carbon.

Research on Two-stage Isolated AC–DC Converter with PSO Optimized PI Control

Zhou Kai,Li Zheng,Wu Xiaogang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

AC–DC converter has the advantages of high power density, stable output, easy to control, etc., and is widely used in many industrial felds. In this paper, the two-stage isolated AC–DC converter is the object of study, and the converter consists of a front-stage Boost PFC converter and a rear-pole LLC resonant converter. The small signal perturbation analysis method and the extended function method are used to construct the equivalent mathematical models of the PFC converter and the LLC resonant converter, and analyze their input and output characteristics and frequency response characteristics. The control strategy based on particle swarm algorithm optimized PI is proposed, and the PSO algorithm optimized PI loop control system is designed on this basis. Simulation software is used to compare the performance indexes of PSO optimized PI control method, and an experimental platform is built to verify it. The results show that the isolated converter can not only meet the requirement of sinusoidal input current on the grid side, but also realize the electrical isolation and ensure the output voltage stability. The PSO algorithm is also introduced to automatically adjust the PI parameters according to the operating state of the converter, so that a faster regulation speed can be obtained during the startup of the converter and the sudden change of the load, and the system as a whole has a better dynamic characteristic and steady state characteristic, and the simulation analysis and experimental sessions verify the correctness of the circuit design and the efectiveness of the control strategy.

Experimental and numerical studies on the frame-infill in-teraction in steel reinforced recycled concrete frames

Jian-yang Xue,Xiaogang Huang,Zheng Luo,Liang Gao 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.6

Masonry infill has a significant effect on stiffness contribution, strength and ductility of masonry-infilled frames. These effects may cause damage of weak floor, torsional damage or short-column failure in structures. This article presents experiments of 1/2.5-scale steel reinforced recycled aggregates concrete (SRRC) frames. Three specimens, with different infill rates consisted of recycled concrete hollow bricks (RCB), were subjected to static cyclic loads. Test phenomena, hysteretic curves and stiffness degradation of the composite structure were analyzed. Furthermore, effects of axial load ratio, aspect ratio, infill thickness and steel ratio on the share of horizontal force supported by the frame and the infill were obtained in the numerical example.