Preparation and SO2 Adsorption Behavior of Coconut Shell-Based Activated Carbon via Microwave-Assisted Oxidant Activation

A series of oxidants supported on coconut shell-based activated carbon(CAC) through microwave irradiation were prepared and characterized using scanning electron microscopy(SEM), N_2 adsorption/desorption analysis, and X-ray photoelectron spectroscopy(XPS). The SO_2 adsorption capacities and rates were evaluated by adsorption tests performed in a fixed bed reactor with a simulated flue gas, and the adsorption isotherm models were validated against the experimental results. The findings revealed that the SO_2 adsorption capacity decreased in the following order: MW-K_2Cr_2O_7-CAC > MWKMnO_4-CAC > MW-H_2O_2-CAC > MW-CAC. The SO_2 adsorption capacities and adsorption rates of the samples increased with an increasing oxidizability of the oxidants owing to the increment of mean pore size and oxygen-containing functional groups. In addition, a high initial SO_2 concentration and a low bed temperature could positively affect the SO2 adsorption. Finally, the Langmuir model validated that SO_2 was mainly adsorbed through chemical adsorption on the sample surfaces.

Adsorption Kinetics and Thermodynamics Study of Butylparaben on Activated Carbon Coconut Based

In this work, low cost coconut biochar based activated carbon (CBAC) was used for adsorption of Butylparaben (BPB) from aqueous medium. The prepared CBAC was characterized using BET, Boehm analysis and the adsorption equilibrium, kinetics and thermodynamics studies of BPB adsorption were carried out. During batch adsorption runs, the effects of factors, such as contact time (0 - 300 min), CBAC dose (200 - 800 mg), pH (3 - 11) and solution temperatures (303 - 348 K) were investigated on BPB removal. Experimental results reveal that the BPB removal efficiency on CBAC is higher than 97% under acidic and neutral conditions. Equilibrium data were fitted by Langmuir, Freundlich and Temkin isotherm models with correlation coefficient more than 0.9. The pseudo-second order kinetic model was observed to fit well the adsorption data. Thermodynamic analysis shows positive values of standard Gibb’s free energy, suggesting the non-spontaneity of the process. The changes in enthalpy (0.2 J.mol-1) and entropy (19 J.mol-1) were found to be endothermic with an increase of randomness. The high adsorption efficiency of the synthesized coconut biochar materials with low cost indicates that it may be a promising adsorbent for removing organic compounds.

Environmentally Friendly Bifunctional Catalyst for ORR and OER from Coconut Shell Particles

Catalyst for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is at the heart of key renewable energy technologies such as water splitting and rechargeable batteries. But developing a low-cost oxygen electrode catalyst with high activity at low overpotential remains a great challenge. Coconut shells can be utilized as suitable raw material to produce activated carbon for enhanced adsorption capacity, bulk density, and hardness to be used as regenerative fuel cells running ORR and OER. The present work is designed to obtain an alternative to noble metal-based catalysts by synthesizing electroactive N-doped porous carbon from coconut shells;the use of biodegradable raw material through a single-step activation followed by nitrogen doping provides a more economical and environmentally friendly route to produce green catalysts for fuel cell applications. In valorization of biomass for the development of novel catalytic materials, our aim is also to reduce the use of hazardous chemicals. N-doped activated carbon shows promising bifunctional catalyst for ORR and OER as low-cost noble-metal-free and carbon-based oxygen catalysts.

椰壳碳@MnO_(2)纳米材料在水系锌离子电池中的应用

为解决MnO_(2)材料在水系锌离子电池(ZIBs)中存在的导电性差、材料利用率低等问题,以农业废弃物椰壳为原料,将低成本、来源丰富、绿色可再生的生物质资源引入到电极材料中,通过高温碳化得到导电性优异的椰壳碳,用水热法在椰壳碳表面生长MnO_(2)纳米粒子,获得椰壳碳@MnO_(2)复合纳米材料。借助扫描电子显微镜(SEM)、X射线衍射仪(XRD)、电化学技术等表征测试手段,分析该复合材料的形貌结构以及电化学性能。结果表明椰壳碳@MnO_(2)在100 mA g^(-1)的电流密度下,经过300次循环,比容量仍高达到344.6 mA h g^(-1),性能远高于商用MnO_(2)材料(64.3 mA h g^(-1));椰壳碳@MnO_(2)优异的导电性,纳米化的结构设计提高了材料利用率,减少了离子扩散路径,带来更快的离子扩散速率,提高了材料的倍率性能,具有良好的应用前景。

椰壳活性炭负载改性锰基催化剂催化燃烧降解甲苯研究

椰壳活性炭凭其较大的比表面积和较好的活化性能,已逐渐成为降解挥发性有机污染物的主要催化剂载体。研究采用浸渍法制备了以多孔椰壳活性炭颗粒作为载体的金属氧化物催化剂,负载了Mn、Co、Fe不同金属元素的单一氧化物和复合金属氧化物,通过XRD、SEM、EDS等研究手段对不同组分的催化剂进行了表征分析。结果表明:通过改变掺杂金属比和焙烧温度可以制得活性不同的催化剂;当金属负载比为Mn∶Co∶Fe=3∶2∶1、焙烧温度为550℃时,催化剂表现出最佳的催化性能。本研究不仅有助于实现固体废物椰壳的资源化利用,达到经济环保的目的,也能为实际环保工作提供技术支持和理论依据。

预氧化处理椰壳制备微孔活性炭及性能研究

以印尼椰壳为原料,通过预氧化、碳化、活化成功制备了比表面积和微孔含量高的椰壳活性炭,预氧化有利于椰壳活性炭比表面积尤其是微孔比表面积的提高。重点考察了预氧化温度对所制备椰壳活性炭收率、密度、表面官能团、孔结构参数的影响。结果表明,预氧化过程中,由于发生了脱水、羟基氧化、脱羧等反应,O/C、羰基、羧基、酯基等含氧官能团的强度均随温度升高而先增强后减弱,在预氧化温度为280℃时达到最大。所制备椰壳活性炭比表面积、孔容、微孔率等随温度升高先升高后下降,在330℃制备的椰壳活性炭各项孔结构参数最优。

电絮凝/活性炭吸附法去除工业废水中亚甲基蓝的实验研究

亚甲基蓝的分子结构稳定,具有热稳定性和光稳定性等特点,采用简单的单一工艺净化亚甲基蓝废水一般效果不佳,通过电絮凝/活性炭吸附耦合工艺对亚甲基蓝模拟废水的处理效果进行了探讨,并对比了此耦合工艺与单一电絮凝工艺和活性炭吸附工艺在同一条件下去除亚甲基蓝的效果。结果表明:电絮凝/活性炭吸附耦合工艺在同一条件下去除亚甲基蓝的能力均强于单一电絮凝工艺和活性炭工艺,且当处理时间为160 min、椰壳活性炭投加量为10 g·L^(-1)、极板间距为1.5 cm、电流密度为6 mA·cm^(-2)、溶液初始质量浓度为50 mg·L^(-1)时,对模拟废水的处理效果最佳,亚甲基蓝的去除率可以达到84.84%。并且通过实验发现该复合体系的动力学特性符合一级动力学模型。

Low-Temperature Denitrification Performance of Cu2O/Activated Carbon Catalysts for Selective Catalytic Reduction of NOx by CO

To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.

Granular Activated Carbon from Wood Originated from Tropical Virgin Forest

This research investigates several woods originated from trees of tropical virgin forest as raw material for the production of granular activated carbon. Mechanical strength of the activated carbons produced was related to wood hardness and lignin content but not to cellulose-lignin ratio. One of the eight woods studied (Dividivi) produced an activated carbon with a high mechanical strength similar to that produced from coconut shell, taken as a standard. Dividivi is also suggested as promissory for desert greening.

椰壳炭吸附去除四环素性能及机理研究

资源化利用椰壳炭作为吸附剂去除水中四环素,对其进行了详细表征,研究了pH值、椰壳炭投加量、四环素初始质量浓度对吸附性能的影响,并探究了吸附机理.结果表明,椰壳炭以微孔和介孔为主,比表面积达478.45 m^(2)·g^(-1).初始质量浓度为50 mg·L^(-1)的四环素废水,投加500 mg·L^(-1)椰壳炭,处理15 min,去除率可达98%.椰壳炭对四环素的吸附符合Langmuir等温吸附模型,以单分子层表面吸附为主,吸附过程符合准一级吸附动力学模型,主要为物理吸附.

椰壳炭负载钌催化剂的制备及其催化氨硼烷水解制氢性能

以椰壳炭(CSC)为载体,通过浸渍-还原法负载活性组分Ru,制得Ru CSC催化剂,利用X射线衍射、X射线光电子能谱、透射电镜和N 2吸附-脱附等一系列表征手段来探究催化剂的微观结构及形貌;进而考察了光照、金属负载量、反应物浓度、催化剂用量、反应温度等因素对氨硼烷水解制氢反应速率的影响。结果表明:Ru与CSC之间存在金属-载体相互作用;以1.0%Ru CSC为催化剂催化氨硼烷水解制氢反应,其在可见光照射条件下的催化性能明显优于无光照条件;氨硼烷水解制氢速率与Ru/CSC浓度呈正相关关系,催化剂的界面反应是氨硼烷水解制氢的控速步骤,与氨硼烷浓度无关;以1.0%Ru CSC在298 K下光催化氨硼烷水解制氢反应的转化频率(TOF)为334.8 min^(-1),表观活化能(E_(a))为59.9 kJ mol。

活性炭的双氧水表面改性及其吸附二氧化硫性能研究

目的制备武器装备贮存微环境用单组分的二氧化硫吸附材料。方法采用双氧水对椰壳活性炭进行表面改性,研究改性活性炭孔隙结构、表面化学性质的变化及其对二氧化硫吸附性能的影响。结果活性炭存在微孔和中孔,改性后活性炭比表面积略有增加,平均孔径减小。双氧水与活性炭反应起到刻蚀作用,在活性炭表面产生了纳米尺度的网孔结构,降低了活性炭表面碳微晶有序程度,同时双氧水与活性炭反应时起到了氧化作用,提升了活性炭表面氧元素和含氧官能团含量。体积分数为20%的双氧水改性活性炭的吸附容量最高,达到154.15 mg/g,约为改性前的5倍。结论双氧水对活性炭经表面改性后,产生了纳米尺度的孔隙,并提升了活性炭表面含氧官能团,在两者协同作用下显著提升活性炭对SO_(2)吸附性能,具有良好的装备应用前景。

Low-temperature Denitration Mechanism of NH_(3)-SCR over Fe/AC Catalyst

To study the modification mechanism of activated carbon(AC)by Fe and the low-temperature NH_(3)-selective catalytic reduction(SCR)denitration mechanism of Fe/AC catalysts,Fe/AC catalysts were prepared using coconut shell AC activated by nitric acid as the support and iron oxide as the active component.The crystal structure,surface morphology,pore structure,functional groups and valence states of the active components of Fe/AC catalysts were characterised by X-ray diffraction,scanning electron microscopy,nitrogen adsorption and desorption,Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy,respectively.The effect of Fe loading and calcination temperature on the low-temperature denitration of NH_(3)-SCR over Fe/AC catalysts was studied using NH_(3)as the reducing gas at low temperature(150℃).The results show that the iron oxide on the Fe/AC catalyst is spherical and uniformly dispersed on the surface of AC,thereby improving the crystallisation performance and increasing the number of active sites and specific surface area on AC in contact with the reaction gas.Hence,a rapid NH_(3)-SCR reaction was realised.When the roasting temperature remains constant,the iron oxide crystals formed by increasing the amount of loading can enter the AC pore structure and accumulate to form more micropores.When the roasting temperature is raised from 400 to 500℃,the iron oxide is mainly transformed fromα-Fe_(2)O_(3)toγ-Fe_(2)O_(3),which improves the iron oxide dispersion and increases its denitration active site,allowing gas adsorption.When the Fe loading amount is 10%,and the roasting temperature is 500℃,the NO removal rate of the Fe/AC catalyst can reach 95%.According to the study,the low-temperature NH_(3)-SCR mechanism of Fe/AC catalyst is proposed,in which the redox reaction between Fe~(2+)and Fe~(3+)will facilitate the formation of reactive oxygen vacancies,which increases the amount of oxygen adsorption on the surface,especially the increase in surface acid sites,and promotes and adsorbs more reaction gases(NH_(3),O_(2),NO).The transformation from the standard SCR reaction to the fast SCR reaction is accelerated.

椰壳炭作为锂离子电池负极材料的电化学性能研究

以椰壳为原料,采用高温热解法和活化法制备了椰壳活性炭负极材料。通过X射线衍射、拉曼光谱、扫描电子显微镜、循环伏安法和电化学阻抗谱图等手段考察了活化处理对椰壳炭结构、形貌以及电化学性能的影响。结果表明,经活化处理的椰壳炭无序化程度高,富含微孔、介孔多孔结构,在0.1 A/g电流密度下,首次放电比容量达到918.22 mAh/g,在1 A/g电流密度下循环200次后放电比容量仍有447 mAh/g。

两种炭吸附剂材料对工业园区污水厂出水中UV_(254)的吸附去除效能

文章选用椰壳活性炭和兰炭活性焦作为吸附剂,开展了吸附去除豫北某工业园区污水厂出水UV_(254)的试验。试验结果表明,兰炭活性焦平均孔径大于椰壳活性炭。在pH值为3~9时,两种炭材料对UV_(254)的吸附都随着pH的升高而降低;在3种动力学模型中,伪二级动力学更适合描述两种炭材料对吸附UV_(254)的过程;相比较于Langmuir等温吸附模型,吸附等温数据更适合Freundlich模型;热力学分析的结果表明,两种材料对UV_(254)的吸附具有自发吸热的特性;在所有的试验中,兰炭活性焦对UV_(254)的吸附效果均优于椰壳活性炭。结果表明,在工业园区污水处理厂二级出水深度处理中,SCAC对UV_(254)去除效果较好。

活化工艺对椰壳柱状活性炭孔隙结构的影响

以椰壳炭化料为原料,经磨粉、混合、压伸成型、炭化制得炭化料,再经不同活化时间、活化温度、活化剂制备椰壳柱状活性炭。采用氮气吸附对活性炭样品进行表征,根据BET方程、密度泛函理论、D-R方程进行分析。结果表明,活化时间延长,微孔容积先增大后减小,次微孔、过渡孔容积增大,特征尺寸增大;活化温度提高,微孔容积增大,次微孔、过渡孔容积减小,特征尺寸减小;以水蒸气作为活化剂,制备的活性炭样品微孔、过渡孔体系发达,特征尺寸小;以水蒸气、CO_(2)混合气体作为活化剂,制备的活性炭样品次微孔体系发达,孔特征尺寸大。

物理活化法制备椰壳活性炭研究

以椰壳炭化料为原料采用水蒸气活化法在不同操作条件下制备得到各种椰壳活性炭.分别研究了水蒸气活化实验中活化时间和活化温度对活性炭的得率、活性炭碘值和苯酚吸附值的影响关系.实验结果表明,活化温度是水蒸气活化法制备椰壳活性炭的最重要的影响因素.在实验范围内,水蒸气活化法制备椰壳活性炭时,宜将活化温度选择在850℃左右,活化时间为120min.