Optimization of Photo-Fenton Catalyst Preparation Based Bamboo Carbon Fiber by Response Surface Methodology

In this paper,the residue from bamboo factory has been used to design photo-Fenton catalyst,which has the advantages of low cost and magnetic recycling.The photo-Fenton catalytic performance of the biocarbon-based catalyst was excellent and its optimal preparation process was also explored by response surface methodology.First,bamboo-carbon fiber was selected as the photo-Fenton catalyst carrier.Subsequently,the surface of the car-bon fiber was modified,with which dopamine,nano-Fe_(3)O_(4) and nano-TiO_(2) were successively loaded by hydro-thermal method.After the single factor tests,four factors including dopamine concentration,ferric chloride mass,P25 titanium dioxide mass and liquid-solid ratio were selected as the characteristic values.The degradation efficiency of photo-Fenton catalyst to methylene blue(MB)solution was treated as the response value.After the analysis of the response surface optimization,it was shown that the significance sequence of the selected 4 factors in terms of the MB degradation efficiency was arranged as follows:dopamine concentration>liquid-solid ratio>P25 titanium dioxide quality>ferric chloride quality.The optimal process parameters of fiber-carbon catalyst were affirmed as follows:the 1.7 mg/mL concentration of dopamine,the 1.2 g mass of ferric chloride,the 0.2 g mass of P25 titanium dioxide and the liquid-solid ratio of 170 mL/g.The experiment-measured average MB degra-dation efficiency performed by the optimized catalyst was 99.3%,which was nearly similar to the model-predicted value of 98.9%.It showed that the prediction model and response surface model were accurate and reliable.The results from response surface optimization could provide a good reference to design bamboo-based Fenton-like catalyst with excellent catalytic performance.

石墨烯涂层在甲苯低温催化燃烧用堇青石负载Pd整体式催化剂中的作用（英文）

对于传统整体催化剂而言,堇青石等基体比表面积低,往往需先涂覆活性氧化铝等高比表面涂层,此外低温催化燃烧反应生成的水和周围空气中的水分会大量吸附于亲水性氧化物涂层表面,导致贵金属催化活性降低,同时,贵金属的分散度也是影响催化剂活性的主要因素.我们利用石墨烯高疏水性、二维平面结构、对苯环强吸附及对贵金属颗粒的高分散与锚定作用等独特性能,发展基于石墨烯涂层的高活性纳米Pd整体催化剂,以改善上述问题.所制备的Pd/石墨烯/堇青石(Pd/Gr/Cor)复合材料作为整体催化剂用于甲苯低温燃烧反应,通过考察催化性能和吸附行为,重点研究了石墨烯涂层的作用.催化性能结果表明,与无石墨烯涂层的传统Pd/Cor催化剂相比,Pd/Gr/Cor催化剂对甲苯的起燃温度从175℃降至132℃,且在水蒸气存在的情况下表现出更好的稳定性.TEM和吸水速率表征表明,石墨烯涂层可显著提高Pd纳米粒子的分散性,提高堇青石载体的疏水性.动力学研究表明,Pd/Gr/Cor催化剂上甲苯催化燃烧符合一级反应动力学规律,活化能为60.93 k J/mol.此外,研究了其吸附行为,包括吸附等温线,吸附动力学和吸附热力学.模拟结果表明,Pd/Gr/Cor催化剂对甲苯具有优异的吸附性能,对甲苯的吸附符合Freundlich模型,为化学吸附.FLm双点位吸附模型表明,石墨烯表面吸附了大量的甲苯,而Pd粒子表面吸附的甲苯相对较少,但亲和力较强.吸附热力学计算表明,石墨烯对甲苯的吸附是一个自发的放热反应,是一个熵减小的过程,表明甲苯分子可在石墨烯上高度有序组装.石墨烯与Pd之间的显著浓度差和亲和力的差距确保了反应过程中甲苯在石墨烯上的快速转移.吸附动力学研究表明,催化剂对甲苯的吸附为快速过程,催化反应为控速步骤.综上,石墨烯涂层不仅可以提高Pd纳米粒子的分散性,提高催化剂的疏水性,在催化反应过程中,还可利用其强吸附能力提高催化剂表面的甲苯浓度,而显著的浓度差和亲和力的差距可作为驱动力为Pd粒子提供甲苯,从而发挥吸附-催化协同作用优势,进一步提高催化性能.

An Investigation on the Visible Characteristics of Four Caesalpiniaceae Wood Species in Gabon

Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pellegr.,Distemonanthus benthamianus and Erythrophleum ivorense A.Chev.The color of four wood species was evaluated to be consistent by the CIELab and CIE1931 color system.The boards of B.bracteosa,M.heitzii and E.ivorense was divided into dark color.The wood color of B.bracteosa had the highest red to green hue,while the wood appearance of D.benthamianus had the brightest and yellowest color within the four wood species.The whiteness of D.benthamianus was significantly higher than the other three wood species,namely tangential section 21.9%and radial section 22.2%.Hence,the color of the four species varied significantly,which was closely related to internal constituents of wood materials.M.heitzii wood had the highest surface glossiness on both tangential and radial section surfaces.The surface glossiness was highly related to the wood microstructure,especially with the pore and groove structure.This study of the visible characteristics provided the indicated knowledge for the application of the four wood species in wood industry.

Biochar-based slow-release of fertilizers for sustainable agriculture:A mini review

Increasing global population and decreasing arable land pose tremendous pressures to agricultural production.The application of conventional chemical fertilizers improves agricultural production,but causes serious environmental problems and significant economic burdens.Biochar gains increasing interest as a soil amendment.Recently,more and more attentions have been paid to biochar-based slowrelease of fertilizers(SRFs)due to the unique properties of biochar.This review summarizes recent advances in the development,synthesis,application,and tentative mechanism of biochar-based SRFs.The development mainly undergoes three stages:(i)soil amendment using biochar,(ii)interactions between nutrients and biochar,and(iii)biochar-based SRFs.Various methods are proposed to improve the fertilizer efficiency of biochar,majorly including in-situ pyrolysis,co-pyrolysis,impregnation,encapsulation,and granulation.Considering the distinct features of different methods,the integrated methods are promising for fabricating effective biochar-based SRFs.The in-depth understanding of the mechanism of nutrient loading and slow release is discussed based on current knowledge.Additionally,the perspectives and challenges of the potential application of biochar-based SRFs are described.Knowledge surveyed from this review indicates that applying biochar-based SRFs is a viable way of promoting sustainable agriculture.