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.

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).

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.

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.

Kinetics Analysis of Coconut Shell Pyrolysis

[Objective] The paper aimed to study kinetics analysis of coconut shell pyrolysis. [Method] Thermo gravimetric analysis was used to study the pyrolysis characteristic of coconut shell at different pyrolysis rates (5, 10, 20 K/min). [Result] The pyrolysis process included 3 stages, water loss, pyrolysis, and thermal condensation. The pyrolysis process can be described through first-order reaction model. With the increasing pyrolysis rate, activation energy in the first stage rose, but activation energy in the second stage reduced. [Conclusion] The study provided theoretical basis for the promotion and application of biomass energy.

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.

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.

The Potentials of Kyanite Particles and Coconut Shell Ash as Strengthener in Aluminum Alloy Composite for Automobile Brake Disc

The use of waste materials to produce engineering components is currently attracting so much interest due to their low cost, availability and environmental impact. In this study, coconut shell ash (CSA) and kyanite particles (KP) produced from coconut shells and kyanite mineral respectively were characterized. X-ray Florence (XRF), X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to analyze the oxide compositions, crystalline phases and microstructures of CSA and KP. The XRF analysis revealed major oxides in CSA and KP as SiO2 and Fe2O3;and Al2O3 and SiO2 respectively. The XRD analysis revealed the presence of Quartz, Hematite, Andradite and Gaultite phases at major peaks in diffractogram of CSA;and Quartz and Beryl phases at major peaks in the diffractogram of KP. The crystallite sizes of the quartz phases in CSA and KP at diffraction angle of 26.72°C and 20.91°C were determined as 638.28 Åand 789.38 Årespectively. From the SEM image of CSA, it was observed that particles of different sizes are present in the microstructure of CSA. The average size of the particles in the microstructure of CSA is 26.24 μm. A similar result was observed in the SEM image of KP and average size of the particles is 3.074 μm. Also, the energy dispersive X-ray (EDX) spectrums of CSA and KP revealed the presence of many elements with calcium as the major element in CSA and Aluminium as major element in KP. The presence of the crystalline phases in CSA (SiO2, Al2O3, andradite, gaultite and hematite) and KP (SiO2 and Al2O3) will make them good strengthening materials for the production of Aluminium based composites that can be used in applications where a good combination of strength and wear characteristics is a basic requirement like brake disc.

Study of Mechanical Behaviour of Coconut Shell Reinforced Polymer Matrix Composite

The morphology and mechanical properties of coconut shell reinforced polyethylene composite have been evaluated to establish the possibility of using it as a new material for engineering applications. Coconut shell reinforced composite was prepared by compacting low density polyethylene matrix with 5% - 25% volume fraction coconut shell particles and the effect of the particles on the mechanical properties of the composite produced was investigated. The result shows that the hardness of the composite increases with increase in coconut shell content though the tensile strength, modulus of elasticity, impact energy and ductility of the composite decreases with increase in the particle content. Scanning Electron Microscopy (SEM) of the composites (with 0% - 25% particles) surfaces indicates poor interfacial interaction between the coconut shell particle and the low density polyethylene matrix. This study therefore exploits the potential of agrobased waste fiber in Nigeria as an alternative particulate material for the development of a new composite.

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.

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.

Evaluation of stearic acid/coconut shell charcoal composite phase change thermal energy storage materials for tankless solar water heater

This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as supporting material was modified by moderate oxidant of H_(2)O_(2)with different concentrations,and then sta-bilized stearic acid(SA)to prepare composite PCMs through vacuum impregnation.It found that CSC support causes a 15.70%improvement of SA loadage after treated by 15%H_(2)O_(2)due to coefficient enhancement by phys-ical interaction and surface modification.The modified CSC 15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC 0 support verifying from SEM and BET results.And the content of oxygen functional groups was increased after oxidation modification,also motivating SA stabiliza-tion by hydrogen bond interaction in XPS analysis.FTIR results proved there is no chemical reaction happened between SA and CSC.Moreover,the latent heat and phase transition temperature of the as-prepared SA/CSC 15 composite are 76.69 J g^(−1)and 52.52℃,respectively.All composites exhibit excellent thermal stability under a working temperature of 180℃and form stability during phase change.Thermal energy storage-release test within 70℃presents the composite has fast heat transfer efficiency than pure SA.The composite filled in TSWH system has 0.75 W m^(−1)K^(−1)thermal conductivity which is 2.88 times higher than that of pure SA(0.26 W m^(−1)K−1).Besides,the TSWH system with a flow rate of 0.004 kg s^(−1)could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h.In all,SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application,especially in solar energy storage.

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。

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。

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。

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.