Nigerian Biomass for Bioenergy Applications:A Review on the Potential and Challenges

Nigeria,often referred to as“the giant of Africa,”boasts a sizable population,a thriving economy,and abundant energy resources.Nevertheless,Nigeria has yet to fully harness its renewable energy potential,despite its enormous capacity in this field.The goal of this review paper is to thoroughly examine the difficulties and untapped opportunities in utilizing biomass for bioenergy production in Nigeria.Notably,Nigeria generates substantial volumes of biomass annually,primarily in the form of agricultural waste,which is often either discarded or burned inefficiently,resulting in significant ecological and environmental damage.Therefore,an efficient approach to reducing pollution and transforming waste into wealth involves converting these biomass resources into energy.This work critically examines the status of biomass utilization for energy applications in Nigeria and highlights the bottlenecks that impede its widespread adoption.The review emphasizes the economic and ecological advantages of biomass utilization over traditional waste treatment methods.Additionally,it underscores the appeal of biomass as an industrial fuel source,particularly considering the current high cost of fossil fuels in contemporary Nigeria.Relevant literature on biomass,energy,agricultural waste,fossil fuel,and calorific value in the context of Nigeria was reviewed by utilizing a thorough search technique in key scientific databases.The analysis did not include any non-English publications.The findings of this research provide valuable insights into the challenges faced in maximizing Nigeria’s biomass potential and offer strategic recommendations to promote the use of biomass for bioenergy development.This review paper will assist a wide range of local and international readers,as well as industries interested in green and bioenergy,in making informed decisions regarding the most suitable types of biomass for biofuel production.

A Comparative Study of Transesterification of Hydnocapus weightiana Seed Oil Using Calcined and Acid Activated Natural Heterogeneous Catalyst and Its Kinetic Study

The world’s total fossil fuel consumption has been significantly increasing with consequential increased environmental catastrophes. A hunt for an alternate energy source was stimulated. Biofuel is a plausible option in this pursuit due to its ideal qualities which included but are not limited to renewability and environmental friendliness. However, the pump price of biodiesel is still very high due mainly to the high cost of the production of the commodity which is influenced by the feedstock and the homogeneous nature of catalyst used. Heterogeneous catalyst was prepared by using Pila globosa sea snail shells prepared by calcination (CP8) and by acid activation (PTW1M). Hydnocapus weightiana seed oil (Non-edible feedstock) was extracted using the soxhlet extraction method and was used for biofuel production with a methanol oil ratio of 3:1. Agitation speed 800, 600 rmp, reaction temperatures of 70°C, 60°C, catalyst concentration (3.00, 2.00 wt%) and reaction time (70 and 60 min) was maintained for CP8 and PTW1M respectively. The rate of the reaction followed a reversible second-order reaction rate. Re-usability accessed. From TGA analysis, the best calcination temperature was 800°C. SEM results showed improved surface morphology after calcination, especially for CP8. FTIR analysis showed the elimination of volatiles and formation of CaO and CaO4Te after calcination. The reaction rate constant at different temperatures was 0.0287 at 30°C, 0.1200 at 50°C and 0.1142 at 70°C and activation energy of the ethyl ester was 49.49 KJ/mol. Using CP8. Most of the fuel properties met with ASTM 6751 standard. The result of the re-usability showed that the biodiesel yield declined as follows: 92, 86, 80, 73 and 69 % for CP8 and 85, 84, 81, 76, 65. For PTW1M. After the fifth regeneration cycle, both CP8 and PTW1M samples of Pila globosa sea snail shell catalyst proved effective in transesterification reaction of Hydnocapus weightiana seed oil using ethanol. It was observed that the calcined catalyst (CP8) showed a superior catalytic performance.

Determination of Plutonium Isotopes in Radioactive Waste Contaminated with Uranium and Thorium

Nucleco is the Sogin Group’s Italian leading company in the sector of radiological services,radioactive waste management,decontamination and reclamation of industrial sites and nuclear power plants.Nucleco is 60%owned by Sogin and 40%by ENEA-National Agency for New Technologies.The waste characterization carried out by Nucleco SpA includes a large variety of radionuclides belonging to the gamma,beta and alpha emitter families.The determination of Uranium and Plutonium isotopes plays a key role in the waste characterization.Nucleco SpA has distinguished itself in characterizations of radioactive waste in complex and nuclear plant matrices.These matrices have large amounts of alpha emitters,in particular isotopes of Uranium,Thorium and Plutonium.A significant presence of U238 results in such a large amount of Th234(and daughters)that interferes with the determination of Pu241.Hence,there is the need of finding a pre-treatment,extraction and subsequent purification technique that would allow Th234 to be detached and thus Pu241 to be determined in complex high-activity matrices.The above elements are extracted using chromatography columns.An isotope of the element to be analyzed,with known activity,is added at the beginning of the process to determine the extraction yield.Before being eluted into the column,the sample undergoes a series of treatments in order to be purified of any interferents.The method developed by Nucleco involves the oxidation of Pu at valence+6 and the subsequent precipitation,in fluorides form,of the elements with valence+4 and+3(i.e.Th234).Pu241 is then measured by LSC(Liquid Scintillation Counting),while the other isotopes are measured by alpha spectrometry after electrodeposition on a metal plate.

真实溶剂似导体屏蔽模型(COSMO-RS)

真实溶剂似导体屏蔽模型(COSMO-RS,Conductor-likescreening model for real solvents)是Klamt等在连续介质溶剂化模式COSMO的基础上,结合统计力学方法发展起来的定量计算溶剂化现象的新方法。本文简单介绍了COSMO-RS的基本原理、概念,以及应用该模式的基本步骤。综述了COSMO-RS应用于离子性化合物、聚合物溶液体系、高温高压体系以及预测复杂生物体系的分配系数和药物设计的进展。评述了简化分子表面屏蔽电荷分布计算的COSMOfrag和GC-COSMO(group contribution COSMO)方法,对不同版本的COSMO-RS之间以及其与基团贡献方法的对比研究也作了详细的讨论,并指出了COSMO-RS的不足之处和进一步发展该模式的建议。

From pollutant to solution of wastewater pollution: Synthesis of activated carbon from textile sludge for dye adsorption

Adsorption is an important process in wastewater treatment,and conversion of waste materials to adsorbent offers a solution to high material cost related to the use of commercial activated carbon.This study investigated the adsorption behaviour of Reactive Black 5(RB5)and methylene blue(MB)onto activated carbon produced from textile sludge(TSAC).The activated carbon was synthesized through chemical activation of precursor followed with carbonization at 650°C under nitrogen flow.Effects of time(0–200 min),pH(2–10),temperature(25–60°C),initial dye concentration(0–200 mg·L^(-1)),and adsorbent dosage(0.01–0.15 g)on dye removal efficiency were investigated.Preliminary screening revealed that TSAC synthesized via H_2SO_4activation showed higher adsorption behaviour than TSAC activated by KCl and ZnCl_2.The adsorption capacity of TSAC was found to be 11.98 mg·g^(-1)(RB5)and 13.27 mg·g^(-1)(MB),and is dependent on adsorption time and initial dye concentration.The adsorption data for both dyes were well fitted to Freundlich isotherm model which explains the heterogeneous nature of TSAC surface.The dye adsorption obeyed pseudo-second order kinetic model,thus chemisorption was the controlling step.This study reveals potential of textile sludge in removal of dyes from aqueous solution,and further studies are required to establish the applicability of the synthesized adsorbent for the treatment of waste water containing toxic dyes from textile industry.

在以EDTA和柠檬酸为配位剂的酸性硫代硫酸盐–亚硫酸盐镀液中电沉积金(英文)

以乙二胺四乙酸或柠檬酸作配位剂,在无氰的硫代硫酸盐–亚硫酸盐体系中研究了金在镀镍铜基底上的电沉积。在温度为60°C,pH为6和电流密度为2A/dm2的条件下,研究了不同配位剂对电流效率、镀速、镀层硬度及镀液分散能力的影响。最佳的镀液组成为0.5mol/L硫代硫酸钠–亚硫酸钠＋0.2mol/L乙二胺四乙酸（或0.3mol/L柠檬酸）。该镀液具有良好的分散能力及高达98%的电流效率。采用扫描电镜、原子力显微镜及X射线衍射分析了镀态金镀层的表面形貌和晶体结构。所得的金镀层几乎无孔（孔隙率〈2-4个/cm2）,结合力良好,硬度适中（80-130HV）。

氨浸出混合铜矿石的表征及动力学(英文)

研究了含8.8％Cu和36.1％Fe的混合铜矿石的氨浸出动力学.矿物学表征表明,该矿石的含铁成分以菱铁矿为主,硫化矿以黄铜矿为主.研究了工艺参数,如搅拌速度、反应温度、氨浓度、矿石粒径、氧分压对氨浸出过程的影响.在标准的浸出条件下,即粒径125～212 μm、反应温度120℃、NH3浓度1.29 mol/L、氧分压202 kPa,在2.5 h内Cu的浸出率达到83％.在使用较高浓度的氨和较小粒径的矿石时,Cu的浸出率能够达到95％.动力学研究结果表明,浸出过程为表面反应控制,估算出的活化能为（37.6±1.9） kJ/mol,氧分压与氨浓度的反应级数分别为0.2和1.

化学镀镍的渗氢测量(英文)

介绍了一种适用于化学镀镍工艺的渗氢测量方法 ,可用于监控渗氢速度 ,测定氢在金属中的扩散 ,研究氢脆 ,评估腐蚀阻化剂和酸洗中钢铁的吸氢等方面。化学镀应用中经常要使用加速剂 ,本研究的目标物质是化学镀镍的加速剂———硫脲及其衍生物。在这些物质存在下 ,化学镀镍过程中的渗氢行为不同。良好的加速剂可减少氢渗 ,加快金属的覆盖。

Synthesis of activated carbon from spent tea leaves for aspirin removal

Adsorption capacity of activated carbon prepared from spent tea leaves(STL-AC) for the removal of aspirin from aqueous solution was investigated in this study. Preliminary studies have shown that treatment with phosphoric acid(H_3PO_4) increased removal efficiency of STL-AC. Characterizations on STL-AC revealed excellent textural properties(1200 m^2·g^(-1), 51% mesoporosity), as well as distinctive surface chemistry(1.08 mmol·g^(-1) and 0.54 mmol·g^(-1) for acidic and basic oxygenated groups, pH_(pzc)= 2.02). Maximum removal efficiency of aspirin observed was 94.28% after 60 min when the initial concentration was 100 mg·L^(-1), 0.5 g of adsorbent used,pH 3 and at a temperature of 30 ℃. The adsorption data were well fitted to the Freundlich isotherm model and obeyed the pseudo-second order kinetics model. The adsorption of aspirin onto STL-AC was exothermic in nature(ΔH~Θ=^(-1)3.808 k J·mol^(-1)) and had a negative entropy change, ΔS~Θ(-41.444 J·mol^(-1)). A negative Gibbs free energy, ΔG~Θ was obtained indicating feasibility and spontaneity of the adsorption process. The adsorption capacity of AC-STL(178.57 mg·g^(-1)) is considerably high compared to most adsorbents synthesized from various sources, due to the well-defined textural properties coupled with surface chemistry of STL-AC which favors aspirin adsorption. The results demonstrate the potential of STL-AC as aspirin adsorbent.

Factors affecting the shrinkage of fly ash geopolymers

The shrinkage of fly ash geopolymers was studied in the present study.Fly ash was used as the source material for making the geopolymers.The effects of the concentration of NaOH,sodium silicate-to-NaOH ratio,liquid-to-ash ratio,curing temperature,and curing time on shrinkage were investigated.The geopolymers were cured at 25,40,and 60℃,respectively.The results indicate that the shrinkage of geopolymers is strongly dependent on curing temperature and liquid-to-ash ratio.The increase in shrinkage is associated with the low strength development of geopolymers.It is also found that NaOH concentration and sodium silicate-to-NaOH ratio also affect the shrinkage of geopolymers but to a lesser extent.

Use of electron microscopy on microstructure characterization of high chromium cast irons

The physical metallurgy underlying the development of cast microstructures in abrasion resistant high chromium cast irons, and their structural modification by thermal treatments is relatively complex. Structural characterisation via electron microscopy therefore has a key role to play in furthering our understanding of the phase transformations that control the microstructures and hence the service performances of these irons as wear parts. This paper shows how both scanning and especially transmission electron microscopy can provide valuable information on the nature of eutectic and secondary carbides and on the matrix structures in these irons. Particular attention is given to current characterisation research on conventionally cast 30%Cr irons that are used for applications involving corrosive wear e.g. slurry pumps and on a semi-solid cast 27%Cr iron that has a potential for applications in industry.

Dissolution kinetics of kaolin mineral in acidic media for predicting optimal condition for alum production

The dissolution kinetics and mechanisms of reaction of Batagbon Kaolin in sulphuric and fluosilicic acids were studied. Leaching temperature, acid concentration, particle size, solid-to-liquid ratio, and stirring speed were selected as process parameters. It is observed that the dissolution rate increases with decreasing particle size and solid-to-liquid ratio, and increases with stirring speed, acid concentration, and leaching temperature. The experimental results indicate that the dissolution rate is of mixed control via hydrogen ion [H^+] action, with reaction order of 0.813 and the reaction kinetics can be expressed as K_mt=[1-(1-x)^(1/3)+y/6[(1-x)^(1/3)+ 1-2(1-x)^(2/3)]. The activation energy of the process is determined to be 21.6 k J/mol. The level of the product quality is also evaluated.

Rhus laccase catalysis and product characterization of 1,2-dimethoxyphenol in organic solutions

Dimethoxyphenol was a widely used substrate in determination of laccases activity. It was surprised, however, that the products of it had not been completely determined until now. Studies were thus conducted on Rhus laccase （RL） and immobilized Rhus laccase （IRL）-catalyzed oxidation of 2,6-dimethoxyphenol （DMP） in water-organic solvent systems. Only one product, 3,3′,5,5′- tetramethoxy-1 ,1′-biphenyl-4,4′-diol （TMBP）, was produced by RL catalysis, and it was thoroughly characterized by FT-IR, NMR and GC-MS, etc.

Applied bias photon-to-current conversion efficiency of ZnO enhanced by hybridization with reduced graphene oxide

The role of reduced graphene oxide（rGO） in the enhancement of photo-conversion efficiency of ZnO films for photoelectrochemical（PEC） water-splitting applications was analyzed. ZnO and rGO-hybridized ZnO（rGO/ZnO） films were prepared via a two-step electrochemical deposition method followed by annealing at 300 °C under argon gas flow. The physical, optical and electrochemical properties of the films were characterized to identify the effect of rGO-hybridization on the applied bias photon-to-current efficiency（ABPE） of ZnO. Scanning electron microscopy and X-ray diffraction indicated the formation of verticallyaligned, wurtzite-phase ZnO nanorods. Diffuse-reflectance UV–visible spectroscopy indicated that rGO-hybridization was able to increase the light absorption range of the rGO/ZnO film. UPS analysis showed that hybridization with rGO increased the band gap of ZnO（3.56 eV） to 3.63 eV for rGO/ZnO sample,which may be attributed to the Burstein–Moss effect. Photoluminescence（PL） spectra disclosed that rGOhybridization suppressed electron-hole recombination due to crystal defects. Linear sweep voltammetry of the prepared thin films showed photocurrent density of 1.0 and 1.8 m A/cm;for ZnO and rGO/ZnO at+0.7 V, which corresponded to an ABPE of 0.55% and 0.95%, respectively. Thus, this report highlighted the multi-faceted role of rGO-hybridization in the enhancement of ZnO photo-conversion efficiency.

Phytochemically Functionalized Cu and Ag Nanoparticles Embedded in MWCNTs for Enhanced Antimicrobial and Anticancer Properties

Nanomedicine is an emerging field concerned with the use of precision engineered nanomaterials, which leads to the development of novel remedial and diagnostic modalities for human use. In this study, Cu(NO_3)_2 and Ag NO_3 precursors were reduced to copper nanoparticles(Cu NPs) and silver nanoparticles(Ag NPs) using Terminalia arjuna bark extracts under microwave irradiation in the presence of well-dispersed multi-walled carbon nanotubes(MWCNTs) in aqueous medium. The formation of Cu NPs or Ag NPs and their functionalization with MWCNTs via bioactive molecules of plant extract were evidenced from UV–Vis spectra, XRD, FTIR, FESEM, EDX, and TEM images. The phytochemically functionalized Cu-MWCNTs and Ag-MWCNTs nanomaterials showed enhanced biocide activity, and the inhibitory activity for bacteria was higher than that of fungus. Furthermore, these biohybrid nanomaterials are non-toxic to normal epithelial cells(Vero), whereas they are highly toxic for tested human cancer cells of MDA-MB-231, He La, Si Ha, and Hep-G2. The cell viability was found to decrease with the increasing dose from 10 to 50 lg m L^(-1), as well as incubation time from 24 to 72 h. For instance, the cell viability was found to be *91 % for normal Vero cells and *76 % for cancer cells for lower dose of 10 lg m L^(-1).

Effects of Heat Treatment on Hardness and Dry Wear Properties of a Semi-Solid Processed Fe-27 wt pct Cr-2.9 wt pct C Cast Iron

EfFects of heat treatments on hardness and dry wear properties of a semi-solid processed Fe-26.96 wt pct Cr- 2.91 wt pct C cast iron were studied. Heat treatments included tempering at 500℃, destabilisation at 1075℃ and destabilisation at 1075℃ plus tempering at 500℃, all followed by air cooling. Electron microscopy revealed that, in the as-cast condition, the primary proeutectic austenite was round in shape while the eutectic M7C3 carbide was found as radiating clusters mixed with directional clusters. Tempering did not change the microstructure significantly when observed by scanning or transmission electron microscopy. Destabilisation followed by air cooling led to a precipitation of secondary M23C6 carbide and a transformation of the primary austenite to martensite. Precipitation behaviour is comparable to that observed in the conventionally cast iron. Tempering after destabilisation resulted in a higher amount of secondary carbide precipitation within the tempered martensite in the eutectic structure. Vickers macrohardness and microhardness in the proeutectic zones were measured. Dry wear properties were tested by using a pin-on-disc method. The maximum hardness and the lowest dry wear rate were obtained from the destabilisation-plus-tempering heat treatment due to the precipitation of secondary carbides within the martensite matrix and a possible reduction in the retained austenite.

Hydrometallurgical Processing of Manganese Ores: A Review

Hydrometallurgy is the most suitable extractive technique for the extraction and purification of manganese as compared to all other techniques including biometallurgy and pyrometallurgical processes. In the hydrometallurgical processing of manganese from its ore, the leach liquors often contain divalent ions such as iron, manganese, copper, nickel, cobalt and zinc along with other impurities which make manganese very difficult to separate. The processes employed for solution concentration and purification in the hydrometallurgical processing of manganese include precipitation, cementation, solvent extraction and ion exchange. Solvent extraction also proves more efficient and it plays vital roles in the purification and separation of the manganese as compared to all other techniques. A detailed review of the various steps involved in the hydrometal-lurgical manganese processing, concentration and purification processes and newer processes of extraction of manganese from ores and waste materials were discussed.

Biosynthesis of silver nanoparticles by using mangrove plant extract and their potential mosquito larvicidal property

Objective:To identify the larvicidal activities of silver nano particles synthesised with Rhizophora mucronata（R.mucronata） leaf extract against the larvae of Aedes aegypti（Ae.aegypti） and Culex quinquefasciatus（Cx.quinquefasciatus）.Methods:In vitro larvicidal activities such as LC50 and LC90 were assessed for the Ae.aegypti and Cx.quinquefasciatus larval species.Further, characterisation such as UV,XRD,FTIR and AFM analysis were carried out for the synthesised silver nano particles.Results:The LC50 value of the synthesised silver nano particle was identified as 0.585 and 0.891 mgg/L for Ae.aegypti and Cx.quinquefasciatus larvae respectively. Further,the LG90 values are also identified as 2.615 and 6.291 mg/L for Ae.aegypti and Cx. quinquefasciatus species respectively.The synthesised silver nanoparticles have maximum absorption at 420 nm with the average size of 60-95 nm.The XRD data showed 20 intense values with various degrees such as 37.10°,47.66°,63.97°and 70.01°.The FTIR data showed prominent peaks in（3 426.89,2 925.49,2 869.56,2 346.95,1 631.49,1 031.73,669.18 and 455.12） different ranges.Conclusions:The biosynthesis of silver nanoparticles with leaf aqueous extract of R. mucronata provides potential source for the larvicidal activity against mosquito borne diseases.

Preparation of PVDF/SiO₂Composite Nanofiber Membrane Using Electrospinning for Polymer Electrolyte Analysis

Superhydrophobic poly(vinylidene fluoride) PVDF-SiO2 composite membranes with different % of SiO2 contents were prepared by electrospinning. The surface morphologies of the membranes are characterized by using scanning electron microscopy. The nanofibers in the membranes were stacked in layers to produce fully interconnected pores that resulted in high porosity. The incorporation of SiO2 into the nanofiber membrane improved the ionic conductivity from 0.2428 × 10-4Scm-1 to 7.731 × 10-4Scm-1 at room temperature. The surface roughness of the membranes increased with increasing the SiO2 content, while the average diameter of nanofibers was rarely affected. Superhydrophobic PVDF membrane with a contact angle larger than 136° was prepared by the electrospinning of the SiO2 functionalized PVDF. The surface composition of the membranes is analyzed by using FTIR and the contact angles and water drops on the surface of the membrane are measured. The contact angle experimental results of PVDF-SiO2 composite membranes showed an improvement of hydrophobicity with % of nano SiO2.

A New CMC-AA Resin/Inorganic-gel Super Absorbent Material

A super absorbent material was prepared with the super absorbent resin （ SAR ） and inorganic gel. The SAR of the carboxymethyl cellulose grafting acrylic acid （ CMC-AA ） was copolymer synthesized using the method of inverse-phase suspension polymerization. The influences of the monomer concentration, neutralization degree, the initiator, dispersion agent, cross-linking agent, reaction and drying temperature on the grafting copolymer properties were examined. Meanwhlie, its properties was investigated and the model for absorption mechanism of this absorbent composite was proposed.