The Response Surface Methodology (RSM) was used to optimise the conditions of preparation of activated hydrochar from tannery solid waste by hydrothermal carbonisation (HTC). The main factors such as residence time, m...The Response Surface Methodology (RSM) was used to optimise the conditions of preparation of activated hydrochar from tannery solid waste by hydrothermal carbonisation (HTC). The main factors such as residence time, moisture content and final carbonisation temperature were investigated during the optimisation of hydrochar preparation conditions. The three responses investigated are hydrochar yield, iodine and methylene blue indices. The results of experimental analyses showed that the yield of hydrochar decreases with increasing final temperature, leading to the formation of micropores inside the carbonaceous solid. The optimum conditions for preparing the following hydrochar were obtained: 83.10%, 390.44 mg∙g−1 and 259.63 mg∙g−1 respectively for the hydrochar yield, the iodine and methylene blue indices. The specific surface area of prepared hydrochar is 849.160 m2/g, SEM micrographs showed a porous heterogeneous surface and particularly, the hydrochar surface also revealed external pores on the hydrochar surface which acted as a pathway to the micropores. Fourier transform infrared (FTIR), however, showed a predominance of acid functions on the surface of the carbonaceous solids. Tests were carried out to eliminate indigo carmine in aqueous media. Activated hydrochar showed a high level of activity, with the Langmuir and Freundlich isotherms giving an adsorption quantity of 354.610 mol/g and a KF constant of 468.2489, respectively. The findings of the research revealed that hydrochar produced is well adapted for dyes removal.展开更多
Co-precipitation method was used for the synthesis of biochar/Fe<sub>3</sub>O<sub>4</sub> to heterogeneously degrade methylene blue (MB) in an aqueous medium. This catalyst was characterized by...Co-precipitation method was used for the synthesis of biochar/Fe<sub>3</sub>O<sub>4</sub> to heterogeneously degrade methylene blue (MB) in an aqueous medium. This catalyst was characterized by different techniques such as Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Raman Microscopy. The analysis highlighted the presence of iron oxides on the surface of the biochar in the form of magnetite (Fe<sub>3</sub>O<sub>4</sub>). Catalytic tests performed on this composite showed significant degradation and simple magnetic separation in the solution for reuse. Maximum degradation was carried out after stirring it for 90 minutes in an MB aqueous solution at different concentrations. The percentages of degradation were 99% and 98.6% 93.3% and 91% for concentrations of MB 40 mg/L and 60 mg/L, 80 mg/L and 120 mg/L respectively. The reactions followed a second-order kinetics with correlation coefficients r<sup>2</sup> = 0.9598, 0.9247, 0.9548 and 0.9614 for the same concentrations of MB at pH = 2, 0.2 mL/L H<sub>2</sub>O<sub>2</sub> and 15 mg of biochar/Fe<sub>3</sub>O<sub>4</sub>. This work provides a simple and an effective method for the preparation of biochar/Fe<sub>3</sub>O<sub>4</sub> and its use for the oxidation of MB by means of heterogeneous Fenton.展开更多
This study is on the adsorption of indigo carmine dye by composite activated carbons prepared from banana pseudo stems and plastic waste. The activated carbons named TB<sub>1</sub>P<sub>1</sub>...This study is on the adsorption of indigo carmine dye by composite activated carbons prepared from banana pseudo stems and plastic waste. The activated carbons named TB<sub>1</sub>P<sub>1</sub>, TB<sub>1</sub>P<sub>1h</sub> and TB<sub>2</sub>P<sub>1</sub> were obtained by pyrolysis at 700<span style="white-space:nowrap;">°</span>C under steam of raw materials at different ratios (1:1 and 2:1). They were characterized by different techniques such as SEM/EDX, Raman Spectroscopy, FTIR, XRD, TGA/DTA and BET/BJH. Analyses indicate amorphous structures with specific surface areas of 424.37;385.45 and 338.84 m<sup>2</sup>/g for TB<sub>1</sub>P<sub>1</sub>, TB<sub>1</sub>P<sub>1h</sub> and TB<sub>2</sub>P<sub>1</sub> respectively. The study of the adsorption of indigo carmine dye by these adsorbents was carried out by varying parameters such as contact time, mass of adsorbent and initial concentration of the dye. The maximum retention is 94.71%, 86.18% and 84.17% for TB<sub>1</sub>P<sub>1</sub>, TB<sub>1</sub>P<sub>1h</sub> and TB<sub>2</sub>P<sub>1</sub> respectively after 60 min of stirring, for a pH = 4.6 using 0.6 g of adsorbents. The adsorption of indigo carmine follows well, the Langmuir model, with the most suitable kinetics as pseudo second order.展开更多
文摘The Response Surface Methodology (RSM) was used to optimise the conditions of preparation of activated hydrochar from tannery solid waste by hydrothermal carbonisation (HTC). The main factors such as residence time, moisture content and final carbonisation temperature were investigated during the optimisation of hydrochar preparation conditions. The three responses investigated are hydrochar yield, iodine and methylene blue indices. The results of experimental analyses showed that the yield of hydrochar decreases with increasing final temperature, leading to the formation of micropores inside the carbonaceous solid. The optimum conditions for preparing the following hydrochar were obtained: 83.10%, 390.44 mg∙g−1 and 259.63 mg∙g−1 respectively for the hydrochar yield, the iodine and methylene blue indices. The specific surface area of prepared hydrochar is 849.160 m2/g, SEM micrographs showed a porous heterogeneous surface and particularly, the hydrochar surface also revealed external pores on the hydrochar surface which acted as a pathway to the micropores. Fourier transform infrared (FTIR), however, showed a predominance of acid functions on the surface of the carbonaceous solids. Tests were carried out to eliminate indigo carmine in aqueous media. Activated hydrochar showed a high level of activity, with the Langmuir and Freundlich isotherms giving an adsorption quantity of 354.610 mol/g and a KF constant of 468.2489, respectively. The findings of the research revealed that hydrochar produced is well adapted for dyes removal.
文摘Co-precipitation method was used for the synthesis of biochar/Fe<sub>3</sub>O<sub>4</sub> to heterogeneously degrade methylene blue (MB) in an aqueous medium. This catalyst was characterized by different techniques such as Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Raman Microscopy. The analysis highlighted the presence of iron oxides on the surface of the biochar in the form of magnetite (Fe<sub>3</sub>O<sub>4</sub>). Catalytic tests performed on this composite showed significant degradation and simple magnetic separation in the solution for reuse. Maximum degradation was carried out after stirring it for 90 minutes in an MB aqueous solution at different concentrations. The percentages of degradation were 99% and 98.6% 93.3% and 91% for concentrations of MB 40 mg/L and 60 mg/L, 80 mg/L and 120 mg/L respectively. The reactions followed a second-order kinetics with correlation coefficients r<sup>2</sup> = 0.9598, 0.9247, 0.9548 and 0.9614 for the same concentrations of MB at pH = 2, 0.2 mL/L H<sub>2</sub>O<sub>2</sub> and 15 mg of biochar/Fe<sub>3</sub>O<sub>4</sub>. This work provides a simple and an effective method for the preparation of biochar/Fe<sub>3</sub>O<sub>4</sub> and its use for the oxidation of MB by means of heterogeneous Fenton.
文摘This study is on the adsorption of indigo carmine dye by composite activated carbons prepared from banana pseudo stems and plastic waste. The activated carbons named TB<sub>1</sub>P<sub>1</sub>, TB<sub>1</sub>P<sub>1h</sub> and TB<sub>2</sub>P<sub>1</sub> were obtained by pyrolysis at 700<span style="white-space:nowrap;">°</span>C under steam of raw materials at different ratios (1:1 and 2:1). They were characterized by different techniques such as SEM/EDX, Raman Spectroscopy, FTIR, XRD, TGA/DTA and BET/BJH. Analyses indicate amorphous structures with specific surface areas of 424.37;385.45 and 338.84 m<sup>2</sup>/g for TB<sub>1</sub>P<sub>1</sub>, TB<sub>1</sub>P<sub>1h</sub> and TB<sub>2</sub>P<sub>1</sub> respectively. The study of the adsorption of indigo carmine dye by these adsorbents was carried out by varying parameters such as contact time, mass of adsorbent and initial concentration of the dye. The maximum retention is 94.71%, 86.18% and 84.17% for TB<sub>1</sub>P<sub>1</sub>, TB<sub>1</sub>P<sub>1h</sub> and TB<sub>2</sub>P<sub>1</sub> respectively after 60 min of stirring, for a pH = 4.6 using 0.6 g of adsorbents. The adsorption of indigo carmine follows well, the Langmuir model, with the most suitable kinetics as pseudo second order.
