Simple and High-Yield Synthesis of a Thinner Layer of Graphenic Carbon from Coconut Shells

Biomass has become of recent interest as a raw material for‘green’graphenic carbon(GC)since it promotes an environmentally friendly approach.Here,we investigate a single pyrolysis route to synthesize GC from coconut shells which provides a simple method and can produce a high yield,thus being convenient for large-scale pro-duction.The pyrolysis involves a stepped holding process at 350℃ for 1 h and at 650℃ or 900℃ for 3 h.The GC sample resulted at the 900℃ pyrolysis has a thinner sheet,a less porous structure,a higher C/O ratio,and an enhanced electrical conductivity than those pyrolyzed at 650℃.The addition of Na3PO4 catalyst has no signifi-cant effects on the GC structures obtained by this route.The single pyrolysis route generates thinner GC sheets compared to the two-step heat treatment followed by the liquid phase exfoliation(LPE)procedure.Nevertheless,the latter method offers a formation of clean samples with a porous or holey feature which has potential for advanced energy-storage applications.

Characterization of Unsaturated Polyester Filled with Waste Coconut Shells, Walnut Shells, and Carbon Fibers

This study aims to evaluate the erosion behavior and the hardness of hybrid composites made of varying amounts of coconut shells,walnut shells,and carbonfibers dispersed in a polyester matrix.MINITAB(L16)Taguchi experiments were used to determine the optimal combination of parameters.In particular,an erosion device con-sisting of a motor with a constantflow rate of 45 L/min,a pump with a diameter of 40 mm,a nozzle with a dia-meter of 5 mm,and a tank made of“perspex glass”55 cm long,30 cm tall,and 25 cm wide was used.The tests were conducted by varying the sample-to-nozzle distance,the pattern angle,and the sand particle size.The results have revealed that the presence of 7.5%by weight of waste coconut shell,for conditions corresponding to 90°angle,sand size 425μm,stand distance 30 cm,gives the best wear resistance(3.04×10^(-5) g/g).Thefiller content and sand particle size affect the erosive rate,with the angle playing a secondary role.The distance between the sample and the nozzle has a weaker effect on erosive wear.The hardness results show that the models(UP-5%carbonfiber-2.5-3.5-4.5-5.5-6.5-7.5 wt.%waste coconut shell)give the best values for prayer compared to the samples(UP-5 wt.%carbonfiber-2.5-3.5-4.5-5.5-6.5-7.5 wt.%waste walnut shell).

Experimental Study of the Water Absorption Kinetics of the Coconut Shells (Nucifera) of Cameroun

The study is focused on the phenomenon of diffusion of water through the shells of two coconut species (coconut nucifera) of Cameroun. The kinetics absorption of water was studied experimentally by the gravimetric method with discontinuous control of the mass of the samples at the temperature of 23℃. The mature coconut shells were cleaned mechanically, cut in a spherical shape and placed in a drying oven with 105℃ for 4 hours before being plunged in distilled water at 23℃. This study made it possible not only to determine the rate of water absorbed, but also to model the water kinetic absorption of the shells. Of the two models tested (Peleg and Page), the Page model predicted very well the experimental data. The Fick law made it possible to evaluate the effective diffusivity coefficients at the initial and final phases of absorption. The effective diffusivity coefficient was given from the Arrhenius equation.

N-Doped rGO-Like Carbon Prepared from Coconut Shell:Structure and Specific Capacitance

An rGO−like carbon compound has been synthesized from biomass,i.e.,old coconut shell,by a carbonization process followed by heating at 400°C for 5 h.The nitrogen doping was achieved by adding the urea(CH4N2O)and stirring at 70°C for 14 h.The morphology and structure of the rGO-like carbon were investigated by electron microscopies and Raman spectroscopy.The presence of C-N functional groups was analyzed by Fourier transform infrared and synchrotron X-ray photoemission spectroscopy,while the particle and the specific capacitance were measured by particle sizer and cyclic voltammetry.The highest specific capacitance of 72.78 F/g is achieved by the sample with 20%urea,having the smallest particles size and the largest surface area.The corresponding sample has shown to be constituted by the appropriate amount of C–N pyrrolic and pyridinic defects.

Experimental Study of the Drying Kinetics of the Coconut Shells (Nucifera) of Cameroon

Water diffusion of two species of coconut shells (CS) nucifera from Cameroon, in the case of drying, was experimentally studied. The experiment was done with the aid of an oven, by the method of gravimetric batch control of the mass of the test samples with the temperatures varied from 70° to 180° Celsius. The shells of mature coconuts from two species were conserved in the laboratory at a temperature ranging between 20° and 23° Celsius for two months before being mechanically cleaned. This study allows not only the determination of the water content of the shells, but also the identification of the drying model. It is thus from the ten model tests, and the statistical analysis shows that the Midilli model best predicted this drying phenomenon. The coefficient of effective diffusion was determined at different temperatures which permitted the evaluation of the activation energy per the Arrhenius equation.

Influence of Plastic and Coconut Shell (Cocos nucifera L.) on the Physico-Mechanical Properties of the 8/6 Composite Rafter

In this paper, the authors aim to propose the use of waste plastics as a binder in a coconut shell reinforcement for the development of an 8/6 size composite rafter to replace the natural 8/6 size backbone in construction. Following a study into the choice of the best proportions, a total of 30 size 8/6 composite rafters with different proportions of 20%, 25%, 30%, 35%, 40% and 50% plastic content were developed. All the 8/6 composite rafters were subjected to mechanical (3-point bending strength and Monnin hardness) and physical (bulk density and water absorption) characterization analyses. The results show that flexural strength increases from 27.56 MPa to 33.30 MPa for proportions ranging from 20% to 35% plastic content. Above 35% plastic, the strength drops to 19.60 MPa for a 50% plastic content. Similarly, the Monnin hardness drops from 9 mm to 5 mm when the plastic content varies from 20 to 50%. As for the results of the physical characterisation, the values obtained for apparent density vary from 0.89 to 1 for proportions varying from 20% to 35% plastic content and drop to 0.94 for 50% plastic content. As for water absorption, values drop from 6.82% to 2.45% when the plastic content increases from 20% to 50%. These mechanical strengths stabilise at 35% plastic content. The development of an 8/6 chevron composite material based on plastic and coconut shell could therefore be a way of recovering waste and solving the problem of deforestation.

生物炭富集-电感耦合等离子体质谱法测定海水中的痕量铅铜

海洋环境中的重金属污染备受关注,准确测定海水中的痕量重金属,对保护海洋环境和人类健康具有重要意义。海水样品的高盐和重金属痕量浓度等特点给仪器分析带来巨大挑战,直接准确测定高盐基质中的低含量重金属元素是非常困难的,须经前处理去除海水中的大量盐分,并对待测元素进行富集,从而消除基体干扰,降低检出限。为实现海水中的痕量铅和铜的绿色分离与快速检测,本文采用吸附脱附的方式,将海水中铅和铜富集在椰壳生物炭上,再用超纯水反复冲洗生物炭,除去盐分基质,经硝酸溶解脱附,脱附液用0.45μm滤膜过滤后利用电感耦合等离子体质谱法(ICP-MS)测定,建立了生物炭富集ICP-MS测定海水中铅和铜含量的方法。两种金属元素在0.10~100μg/L范围内线性关系良好,线性相关系数均大于0.9995。海水中铅和铜,方法检出限分别为0.005μg/L和0.006μg/L,测定下限分别为0.020μg/L和0.024μg/L,满足《海水、海洋沉积物和海洋生物质量评价技术规范》(HJ 1300—2023)规定的海水质量评价要求。海水样品加标回收率在96.1%~102.3%范围内,相对标准偏差小于5%。本方法操作简便、分析成本低、绿色环保,更适合于基层海洋监测应用,也可用于高矿化度基体样品的水质监测。

球磨法制备堇青石负载Fe/Ce载氧体的甲烷化学链重整性能

通过球磨法制备一系列堇青石负载Fe/Ce的复合载氧体,并在固定床装置上评价复合载氧体的甲烷化学链重整的反应性能。系统考察了堇青石质量分数、Fe/Ce摩尔比、椰壳添加量以及球磨参数对复合载氧体的氧化还原性能的影响,并进行了一系列表征(XRD、H2-TPR、BET、SEM、XPS)。研究发现,在球料比10∶1、转速500r/min、时间1h的球磨参数下制备质量分数30%堇青石负载Fe/Ce摩尔比为1∶9的复合载氧体具有较优的氧化还原性能。质量分数15%椰壳炭的添加使复合载氧体的实际出氧量提升了38.7%,并且在还原氧化循环反应中表现出良好的稳定性和氧释放能力。

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。

不同水分条件下椰壳炭施用对稻田土壤酶活性及微生物群落的影响

以热带稻田土壤为研究对象,利用室内短期恒温(25℃)培养探讨好氧和淹水条件下椰壳炭不同施用量(0%、2%和5%(w/w))对土壤性质和微生物群落的影响。结果表明:①培养35 d后,好氧和淹水条件下增施2%和5%椰壳炭均提升土壤pH,增幅分别为20%、39%和31%、32%。好氧下土壤脲酶活性增加121%和75%,酸性磷酸酶活性降低10%和49%,碱性磷酸酶活性提高39%和39%;淹水下脲酶活性减少12%和45%,酸性磷酸酶活性降低3%和14%,碱性磷酸酶活性增加133%和105%。②增施2%和5%椰壳炭时,好氧下土壤细菌和真菌香农指数均降低,但淹水时增加。好氧下变形杆菌门(Proteobacteria)、芽单胞菌门(Gemmatimonadetes)和浮霉菌门(Planctomycetes)丰度提高,增幅分别为2%、54%,51%、47%和94%、82%;淹水下酸杆菌门(Acidobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)丰度增加,增幅分别为3%、20%,14%、18%和38%、37%;同时好氧和淹水下土壤担子菌门(Basidiomycota)丰度均下降,降幅分别为68%、70%和68%、76%,并且淹水下壶菌门(Chytridiomycota)和罗兹菌门(Rozellomycota)丰度增加。该研究结果可为椰壳炭对稻田土壤改良及其推广应用提供参考。

不同龄期生物炭混凝土力学性能试验研究

将生物炭用于混凝土材料可改善其力学性能,实现固碳的同时丰富了生物质材料固废利用的途径。为研究不同龄期下椰壳、玉米秸秆、稻壳3种生物炭混凝土的工作性能与力学性能,将它以不同质量百分比替代水泥制备生物炭混凝土,对生物碳混凝土的塌落度、基本力学性能展开试验研究。采用SEM和XRD观察生物炭混凝土微观结构与水化产物。结果表明微观结构上生物炭促进了混凝土中水化硅酸钙的生成,水化产物间搭接密实,填充内部孔隙,增加密实程度,进而提升混凝土的宏观力学性能;生物炭可使混凝土7、14 d早期强度显著提升,早期抗压强度最高可提升19.7%,劈裂抗拉强度最高可提升21.7%,抗折强度最高可提升17.3%。

疏水性椰壳纤维的制备及其对油水体系的分离性能

将椰壳纤维经过碱处理、甲基三甲氧基硅烷(MTMS)疏水化改性制备了具有孔隙结构的疏水椰壳纤维吸附材料(HCF)。通过SEM、EDS、FT-IR、XRD对HCF的表面形貌及化学结构进行了表征,通过静态水接触角研究了HCF的表面润湿性能。结果表明,HCF的静态水接触角为126°,在不同pH的溶液中水接触角都保持在125°以上。HCF对原油、泵油、葵花籽油、机油、大豆油、四氯化碳等油类及有机溶剂的吸附倍率为8.49~12.88 g/g,在3 min内达到吸附饱和,具有较好的吸附量和较快的吸附速率。在0.09 MPa压力下,HCF可用于水上浮油的连续分离过程,分离通量为57 326.14 L/(m^(2)·h),分离效率为97.02%,具有一定的处理大量油水混合物的能力。HCF经过10次循环后依然保持良好的吸附性能,具有很好的使用稳定性。

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。

MXene/椰壳炭复合材料的制备及电化学性能分析

MXene具有与金属材料相似的能带结构,并表现出良好的导电性能。但是MXene极易发生层状堆积,影响MXene材料的电化学性能。本研究拟采用MXene和椰壳碳在去离子水中混合制备MXene复合材料,研究其结构和形态对其电化学性质的影响。研究结果表明,加入到MXene薄膜中的可溶性椰壳炭,通过粒子之间的相互渗透对锂离子的迁移起到促进作用。对该材料进行了充放电实验结果表明,采用质量配比1∶2的材料,在电流密度0.1 A/g条件下,其首次充放电比容量可以达到1951.7 m Ah/g,经过200次循环后,其充放电比容量为800.8 m Ah/g。

海南椰壳在中的应用与研究

我国沿海地区种植椰树广泛,比如海南、福建、广西等省市的部分城市和乡村,特别是海南的海口和文昌,种植的椰树面积广,果实产量丰富。“椰子全身是宝”,不仅椰汁清甜,椰肉香脆,而椰壳可以作为一种绿色环保、可再生产品的外包装。在设计应用上,椰壳因其自身独特材质与造型,演绎出了椰碗、椰勺、椰壳活性炭、椰壳茶具等用具,将生态包装得以完美体现。鉴于椰壳容器在长时间储藏、收纳和密封等方面的优势,因此被广泛运用于包装茶叶,椰壳自带的淡淡椰香与茶香融合,造就了独特的海南地方茶叶,深受消费者喜爱。

Removal of Bi(Ⅲ) with Adsorption Technique Using Coconut Shell Activated Carbon

In present study,we report the preparation of coconut shell activated carbon as adsorbent and its appli-cation for Bi(Ⅲ) removal from aqueous solutions.The developed adsorbent was characterized with scanning elec-tron microscope(SEM),Fourier Transform Infrared(FTIR),C,H,N,S analyzer,and BET surface area analyzer.The parameters examined include agitation time,initial concentration of Bi(Ⅲ),adsorbent dose and temperature.The maximum adsorption of Bi(Ⅲ)(98.72%) was observed at 250 mg·L-1 of Bi(Ⅲ) and adsorbent dose of 0.7 g when agitation was at 160 r·min-1 for 240 min at(299±2) K.The thermodynamic parameters such as Gibb's free energy(△Gθ),enthalpy(△Hθ) and entropy(△Sθ) were evaluated.For the isotherm models applied to adsorption study,the Langmuir isotherm model fits better than the Freundlich isotherm.The maximum adsorption capacity from the Langmuir isotherm was 54.35 mg?g?1 of Bi(Ⅲ).The kinetic study of the adsorption shows that the pseudo second order model is more appropriate than the pseudo first order model.The result shows that,coconut shell ac-tivated carbon is an effective adsorbent to remove Bi(Ⅲ) from aqueous solutions with good adsorption capacity.

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.