Recent Application of Core-Shell Nanostructured Catalysts for CO2 Thermocatalytic Conversion Processes

Carbon-intensive industries must deem carbon capture, utilization, and storage initiatives to mitigate rising CO₂ concentration by 2050. A 45% national reduction in CO₂ emissions has been projected by government to realize net zero carbon in 2030. CO₂ utilization is the prominent solution to curb not only CO₂ but other greenhouse gases, such as methane, on a large scale. For decades, thermocatalytic CO₂ conversions into clean fuels and specialty chemicals through catalytic CO₂ hydrogenation and CO₂ reforming using green hydrogen and pure methane sources have been under scrutiny. However, these processes are still immature for industrial applications because of their thermodynamic and kinetic limitations caused by rapid catalyst deactivation due to fouling, sintering, and poisoning under harsh conditions. Therefore, a key research focus on thermocatalytic CO₂ conversion is to develop high-performance and selective catalysts even at low temperatures while suppressing side reactions. Conventional catalysts suffer from a lack of precise structural control, which is detrimental toward selectivity, activity, and stability. Core-shell is a recently emerged nanomaterial that offers confinement effect to preserve multiple functionalities from sintering in CO₂ conversions. Substantial progress has been achieved to implement core-shell in direct or indirect thermocatalytic CO₂ reactions, such as methanation, methanol synthesis, Fischer-Tropsch synthesis, and dry reforming methane. However, cost-effective and simple synthesis methods and feasible mechanisms on core-shell catalysts remain to be developed. This review provides insights into recent works on core-shell catalysts for thermocatalytic CO₂ conversion into syngas and fuels.

Structural characterization of microcrystalline and nanocrystalline cellulose from Ananas comosus L. leaves: Cytocompatibility and molecular docking studies

The present study focused on the preparation of microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) from pineapple (Ananas comosus L.) leaves using chemical treatments followed by acid hydrolysis. Pineapple leaves could be used in medical applications such as drug delivery carriers. Advanced spectroscopy techniques such as Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the physical, chemical, and morphological features of the isolated MCC and NCC; the results indicated the needle-shaped form of nanostructures with good purity and high crystallinity index of 75.00 and 76.38%, respectively. In addition, inhibition of the treated MRC-5 cells with all the samples revealed that the percentage of cell viability was less than 30%, which is an interesting finding given their role in the cytotoxicity effect of MCC and NCC. It appears that MCC and NCC derived from pineapple leaves have lower toxicity. As a result, the developed MCC and NCC can be used in pharmaceutical applications as a novel drug delivery system. Molecular docking was performed to understand the non-bonding interaction of cellulose with human acid-beta-glucosidase (β-Glc) (PDB: 1OGS). The docking result shows that cellulose unit docked within the active pocket of the enzyme by forming hydrogen bonds against ASN19, THR21, and VAL17 with distances of 2.18, 1.93, and 2.92 Å, respectively, with binding energy (−5.0 kcal/mol) resulting in close interaction of cellulose unit with the receptor.

Nanocellulose from agricultural waste as an emerging material for nanotechnology applications – an overview

It has been shown that in the last decades nanotechnology plays a key role not only in science but more and more often in industry as well. Recent research has shown that agricultural waste is a possible feedstock to produce  nanocellulose  which can be used for different applications, such as a biosensor, semiconductor and reinforcing agent. The use of agro-waste as a precursor not only offers advantages for raw material costs, but also for the climate, low processing costs, availability and convenience. It also helps to address environmental issues, such as illness, foul odor and concerns with indoor use. Different processes, such as chemical treatment, mechanical treatment and chemo-mechanical treatment, have been used to extract nanocellulose from agro-waste. This article highlights the latest technologies used to acquire agro-waste nanocellulose, as well as existing advances in and applications of nanocellulose technologies.

Novel cost-effective synthesis of non-doped turbostratic graphene from a graphite intercalation compound: development of a durable and stable electrocatalyst for the oxygen reduction reaction

A cost-effective novel preparation of turbostratic graphene and its efficient use as an electrocatalyst for the oxygen reduction reaction is presented here.

In vitro antioxidant activity of Ficus carica L. latex from 18 different cultivars

As synthetic antioxidants that are widely used in foods are known to cause detrimental health effects, studies on natural additives as potential antioxidants are becoming increasingly important. In this work, the total phenolic content (TPC) and antioxidant activity of Ficus carica Linn latex from 18 cultivars were investigated. The TPC of latex was calculated using the Folin–Ciocalteu assay. 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ferric ion reducing antioxidant power (FRAP) were used for antioxidant activity assessment. The bioactive compounds from F. carica latex were extracted via maceration and ultrasound-assisted extraction (UAE) with 75% ethanol as solvent. Under the same extraction conditions, the latex of cultivar ‘White Genoa’ showed the highest antioxidant activity of 65.91% ± 1.73% and 61.07% ± 1.65% in DPPH, 98.96% ± 1.06% and 83.04% ± 2.16% in ABTS, and 27.08 ± 0.34 and 24.94 ± 0.84 mg TE/g latex in FRAP assay via maceration and UAE, respectively. The TPC of ‘White Genoa’ was 315.26 ± 6.14 and 298.52 ± 9.20 µg GAE/mL via the two extraction methods, respectively. The overall results of this work showed that F. carica latex is a potential natural source of antioxidants. This finding is useful for further advancements in the fields of food supplements, food additives and drug synthesis in the future.

Extraction of Microcrystalline Cellulose from Two Different Agriculture Waste via Chemical Treatment

Microcrystalline cellulose (MCC) was successfully extracted from coconut husk fibre (CHF) and pineapple leaf fibres (PLF) using alkali and bleaching treatments. The extracted cellulose from the chemical treatments were characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). XRD analysis revealed that the extracted microcellulose from CHF and PLF using chemical treatments have high crystallinity. The thermal stability analysis of the extracted microcrystalline celluloses was investigated revealed that the CHF and PLF lose their lignin and hemicellulose during chemical treatments. Morphological investigation using SEM shows that chemical treatment could remove the layer of extractives from surface of CHF and PLF.

RNA-seq data of the Jatropha curcas L. shoot system

Jatropha curcas L. or the physic nut is a monoecious shrub belonging to the Euphorbiaceae family. The plant is an ideal feedstock for biodiesel production; oil-rich seed (37–42%), has a broad range of growth habitat such as arid, semi-arid and tropical and a relatively feasible process for conversion of crude oil into biodiesel. The major constraint affecting the success of large-scale J. curcas plantation is seed yield inconsistency. Numerous research projects conducted on J. curcas with integrated genetic, genomic and transcriptomic approaches have been applied on the leaf, apical meristem, flower, root and fruit tissues. However, to date, no genomics data of J. curcas shoot system are publicly available, despite its importance in understanding flowering, fruiting and seed set qualities targeted for yield improvement. Here, we present eighteen sets of shoot and inflorescence transcriptomes generated from J. curcas plants with contrasting yields. Raw reads of the RNA-seq data are found in NCBI׳s Sequence Read Archive (SRA) database with the accession number SRP090662 (https://www.ncbi.nlm.nih.gov/sra/?term=SRP090662). This transcriptomic data could be integrated with the present genomic resources for in depth understanding of J. curcas reproductive system.

Growth improvement and metabolic profiling of native and commercial Chlorella sorokiniana strains acclimatized in recycled agricultural wastewater

This study investigated acclimation ability of native Chlorella sorokiniana (CS-N) and commercial Chlorella sorokiniana (CS-C) in palm oil mill effluent (POME), their metabolic profile and feasibility of effluent recycling for dilution purpose. Maximum specific growth rate, µ_max and lag time, λ of the microalgae were evaluated. Result shows both strains produced comparable growth in POME, with µ_max of 0.31 day^-1 and 0.30 day^-1 respectively, albeit longer λ by the CS-C. However, three cycles of acclimation was able to reduce λ from eight days to two days for CS-C. Metabolic profiling using principal component analysis (PCA) shows clear cluster of acclimatized strains to suggest better stress tolerance of CS-N. Finally, a remarkable µ_max of 0.57 day^-1 without lag phase was achieved using acclimatized CS-N in 40% POME concentration. Acclimation has successfully shortened the λ and dilution with final effluent was proved to be feasible for further improvement of the microalgae growth.

Catalytic decomposition of undiluted methane into hydrogen and carbon nanotubes over Pt promoted Ni/CeO2 catalysts

A series of Pt promoted Ni/CeO₂ catalysts were prepared and characterized, and their catalytic activity for methane decomposition was reported.

Degradation and mineralization of methylene blue using a heterogeneous photo-Fenton catalyst under visible and solar light irradiation

A SiO₂-supported Fe and Ni bimetallic catalyst has been synthesized, characterized and, for the first time, tested as a heterogeneous photo-Fenton catalyst for the degradation and mineralization of methylene blue (MB) dye.

Methane decomposition over unsupported mesoporous nickel ferrites: effect of reaction temperature on the catalytic activity and properties of the produced nanocarbon

Unsupported mesoporous nickel ferrites were successfully synthesized via a facile co-precipitation method and used for the thermocatalytic decomposition of methane into hydrogen and nanocarbon at various reaction temperatures.

Sodium aluminate from waste aluminium source as catalyst for the transesterification of Jatropha oil

Transesterification of Jatropha oil with methanol is carried over heterogeneous sodium aluminate catalyst to produce biodiesel.

An overview: biomolecules from microalgae for animal feed and aquaculture

Despite being more popular for biofuel, microalgae have gained a lot of attention as a source of biomolecules and biomass for feed purposes. Algae farming can be established using land as well as sea and strategies can be designed in order to gain the products of specific interest in the optimal way. A general overview of the contributions of Algae to meet the requirements of nutrients in animal/aquaculture feed is presented in this study. In addition to its applications in animal/aquaculture feed, algae can produce a number of biomolecules including astaxanthin, lutein, beta-carotene, chlorophyll, phycobiliprotein, Polyunsaturated Fatty Acids (PUFAs), beta-1,3-glucan, and pharmaceutical and nutraceutical compounds which have been reviewed with respect to their commercial importance and current status. The review is further extended to highlight the adequate utilization of value added products in the feeds for livestock, poultry and aquaculture (with emphasis in shrimp farming).

Estimation of Bioethanol Production from <i>Jatropha</i> c<i>urcas</i> Using Neural Network

Fossil fuel is one of the main energy sources for almost all country in the world. However, it is non-renewable energy source, not environmental friendly and the limited supply of the fossil fuel encouraged the scientist to discover other alternative way of new renewable energy supply. New alternative source should be considered for prolonged lifetime. Thus, non-conventional energy sources should be placed in the prior consideration, for instant bioethanol. Jatropha curcas seed is a toxic substance; however, it has a very high oil content which is approximately 3545%. After the extraction of oil from the seed, Jatropha seed cake is formed. In the pressed seed cake, it is found that it contains cellulose and glucose that can be used as substrate in bioethanol production. The production of bioethanol can be estimated by neural network using data from previous research. A programme using MATLAB 7.8 was used to develop the neural network. The software consists of Neural Network Toolbox which functions to train the input data and estimate the production of glucose and bioethanol as output data. An input layer represents the criteria of the production properties of glucose and bioethanol concentration. The hidden layer determines either the input data can be proceed to further production of glucose and bioethanol, whereas the output layer gives the estimation values of glucose and bioethanol production. Back propagation algorithm with TANSIG transfer function was used to accomplish the estimation of production of bioethanol. The error value given by the network was 0.0390. Thus, training sessions were considered successful. Therefore, the users could determine and estimate the production of glucose and bioethanol concentration in just a short period of time.

Carbon Derived from Jatropha Seed Hull as a Potential Green Adsorbent for Cadmium (II) Removal from Wastewater

Carbon from jatropha seed hull (JC) was prepared to study the adsorption of cadmium ions (Cd²⁺) from aqueous solutions under various experimental conditions. Batch equilibrium methods have been used to study the influences of the initial metal ion concentration (0.5-50 ppm), dosage (0.2-1 g), contact time (0-300 min), pH (2-7), and temperature (26-60 °C) on adsorption behavior. It has been found that the amount of cadmium adsorbed increases with the initial metal ion concentration, temperature, pH, contact time, and amount of adsorbent. A kinetic study proved that the mechanism of Cd²⁺ adsorption on JC followed a three steps process, confirmed by an intraparticle diffusion model: rapid adsorption of metal ions, a transition phase, and nearly flat plateau section. The experimental results also showed that the Cd²⁺ adsorption process followed pseudo-second-order kinetics. The Langmuir and Freundlich adsorption isotherm models were used to describe the experimental data, with the former exhibiting a better correlation coefficient than the latter (R² = 0.999). The monolayer adsorption capacity of JC has been compared with the capacities of the other reported agriculturally-based adsorbents. It has been clearly demonstrated that this agricultural waste generated by the biofuel industry can be considered a potential low-cost adsorbent for the removal of Cd²⁺ from industrial effluents.

Utilization of palm empty fruit bunch for the production of biodiesel from Jatropha curcas oil

Transesterification reaction of Jatropha curcas oil with methanol was carried out in the presence of ash generated from Palm empty fruit bunch (EFB) in a heterogeneous catalyzed process. The ash was doped with KOH by impregnation to achieve a potassium level of 20 wt.%. Under optimum conditions for the EFB-catalyzed (65 °C, oil/methanol ratio of 15, 90 min, 20 wt.% EFB ash catalyst) and the KOH-EFB-catalyzed reactions (65 °C, oil/methanol ratio of 15, 45 min, 15 wt.% of KOH doped EFB ash), biodiesel (>98%) with specifications higher than those stipulated by European biodiesel quality standard EN 14214 was obtained.

Electrocoagulation of palm oil mill effluent as wastewater treatment and hydrogen production using electrode aluminum

Palm oil mill effluent (POME) is highly polluting wastewater generated from the palm oil milling process. Palm oil mill effluent was used as an electrolyte without any additive or pretreatment to perform electrocoagulation (EC) using electricity (direct current) ranging from 2 to 4 volts in the presence of aluminum electrodes with a reactor volume of 20 L. The production of hydrogen gas, removal of chemical oxygen demand (COD), and turbidity as a result of electrocoagulation of POME were determined. The results show that EC can reduce the COD and turbidity of POME by 57 and 62%, respectively, in addition to the 42% hydrogen production. Hydrogen production was also helpful to remove the lighter suspended solids toward the surface. The production of Al(OH)XHO at the aluminum electrode (anode) was responsible for the flocculation-coagulation process of suspended solids followed by sedimentation under gravity. The production of hydrogen gas from POME during EC was also compared with hydrogen gas production by electrolysis of tap water at pH 4 and tap water without pH adjustment under the same conditions. The main advantage of this study is to produce hydrogen gas while treating POME with EC to reduce COD and turbidity effectively.