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Investigation on the Preparation and Adsorption Performance of Bamboo Fiber Based Activated Carbon
Qing Zhang,Yue Zeng,Xiuyun Xiao,Penghu Deng,Qing He,Tonghua Zhang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.2
In this work, an approach was explored to make natural fiber based activated carbon with high adsorption capacity for treating dyeing wastewater. Bamboo fiber based activated carbon (BFAC) was prepared by bamboo fiber extracted from bamboo strips by extracting technique. An orthogonal experiment was carried out to obtain optimum preparation condition for the best dye adsorption. The microstructures of BFAC were characterized by scanning electron microscopy, N2 adsorption-desorption analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. Adsorption mechanism of BFAC to methylene blue (MB) was studied and the adsorption isotherm followed the Langmuir model, with maximum monolayer adsorption capacity of 651.7 mg g-1. The adsorption kinetic was better described by the pseudo-second-order model. Microstructure characterization showed lots of opened pores and cracks with different size on BFAC, with Brunauer-Emmett-Teller (BET) surface area of 1370 m2 g-1 and total pore volume of 0.9411 cm3 g-1. The analysis indicated that cellulose crystal of bamboo fiber was severely destroyed in the preparation process, which could contribute to the formation of pores. Moreover, -OH and -C=O functional groups on BFAC are beneficial for adsorbing MB in aqueous solution. As a result, adopting bamboo fiber may help form BFAC with high BET surface area, which proved to be an effective idea to prepare activated carbon with high adsorption performance.
Yu Yang,Tonghua Zhang 대한수학회 2016 대한수학회보 Vol.53 No.1
In this paper, we study a modified stochastic predator-prey system with general ratio-dependent functional response. We prove that the system has a unique positive solution for given positive initial value. Then we investigate the persistence and extinction of this stochastic system. At the end, we give some numerical simulations, which support our theoretical conclusions well.
Global stability of the positive equilibrium of a mathematical model for unstirred membrane reactors
Yongli Song,Tonghua Zhang 대한수학회 2017 대한수학회보 Vol.54 No.2
This paper devotes to the study of a diffusive model for unstirred membrane reactors with maintenance energy subject to a homogeneous Neumann boundary condition. It shows that the unique constant steady state is globally asymptotically stable when it exists. This result further implies the non-existence of the non-uniform steady state solution.
GLOBAL STABILITY OF THE POSITIVE EQUILIBRIUM OF A MATHEMATICAL MODEL FOR UNSTIRRED MEMBRANE REACTORS
Song, Yongli,Zhang, Tonghua Korean Mathematical Society 2017 대한수학회보 Vol.54 No.2
This paper devotes to the study of a diffusive model for unstirred membrane reactors with maintenance energy subject to a homogeneous Neumann boundary condition. It shows that the unique constant steady state is globally asymptotically stable when it exists. This result further implies the non-existence of the non-uniform steady state solution.
Yang, Yu,Zhang, Tonghua Korean Mathematical Society 2016 대한수학회보 Vol.53 No.1
Abstract. In this paper, we study a modified stochastic predator-prey system with general ratio-dependent functional response. We prove that the system has a unique positive solution for given positive initial value. Then we investigate the persistence and extinction of this stochastic system. At the end, we give some numerical simulations, which support our theoretical conclusions well.
Tensile Properties and Structure Characterization of Palm Fibers by Alkali Treatment
Ying Jiang,Penghu Deng,Lingxiao Jing,Tonghua Zhang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.5
This work aims to reveal how the alkali influences the mechanical behavior and structural stability of palm fiber. First, palm fiber samples were treated with 20 % and 40 % NaOH solutions separately for approximately 1, 2, 3, and 4 h atroom temperature. Then the samples were characterized using tensile testing, Fourier transform infrared spectroscopy, X-raydiffraction, and thermogravimetric analysis. Results showed the tensile properties of alkali-treated fibers exceeded those ofuntreated fibers. Notably, the fibers treated with 40 % NaOH for 1 h yielded the most significant improvements. The tensilestrength, elongation at break, Young’s modulus, and yield point increased by 28.8 %, 38 %, 52.1 %, and 64.7 %, respectively,compared with the untreated fibers. The increase appeared to be due to the removal of non-cellulosic materials andrearrangement of the cellulose chains.