This review presents the technical and operational performances of solar and biomass energy technologies viz photovoltaic thermal (PVT) and biomass gasification systems. This work aims to offer a ...reference and guidelines to the renewable energy‐related players, especially for those at the operational level and investors. This paper highlights the technical advantage of hybrid PVT with phase change material in terms of electrical and thermal efficiencies. While the operational performance of biomass gasification is thoroughly discussed via sensitivity analysis, the potential integration between solar and biomass gasification technologies is explored to complement and bolster the capabilities of both renewable systems within the power energy mix portfolio. Finally, few directions and significant takeaways considering the technical criteria are addressed for identifying efficient renewable energy generation.
Industrial and economic growth have encouraged more energy demand. Overconsumption of nonrenewable sources has enormous environmental impacts. Thus, cheaper, renewable, and ecofriendly options are essential. This study examines photovoltaic thermal and biomass gasification system performance. Ultimately, efficient renewable energy production standards are explored.
Heavy metals released by various industries are among the major pollutants found in water resources. In this research, biosorption technique was employed to remove cadmium (Cd
2+
) from an aqueous ...system using a novel biosorbent developed from okara waste (OW), a residue from soya bean–based food and beverage processing. Characterisation results revealed that the OW biosorbent contained functional groups such as hydroxyl-, carboxyl- and sulphur-based functional groups, and the surface of the biosorbent was rough with multiple fissures which might be the binding sites for the pollutant. The effects of dosage, solution pH, initial Cd
2+
concentration, temperature and contact time were investigated using batch adsorption mode. The biosorption equilibrium and kinetic were best described by the Langmuir and Elovich models, respectively. The maximum biosorption capacities predicted by the Langmuir model were 10.91–14.80 mg/g at 30–70 °C, and the biosorption process was favourable as evident from 0 <
R
L
< 1. The uptake of Cd
2+
by the OW biosorbent was spontaneous and endothermic. The plausible biosorption mechanisms of this study could be ionic exchange, hydrogen bonding and electrostatic interactions. The Cd
2+
loaded OW biosorbent could be regenerated using 0.4 M of HCl solution and regeneration was studied for 4 adsorption-desorption cycles. The present investigation supported that OW can be reused as a value-added biosorbent product for the removal of Cd
2+
from the contaminated water.
Pharmaceutical residues are emerging pollutants in the aquatic environment and their removal by conventional wastewater treatment methods has proven to be ineffective. This research aimed to develop ...a three-dimensional reduced graphene oxide aerogel (rGOA) for the removal of diclofenac in aqueous solution. The preparation of rGOA involved facile self-assembly of graphene oxide under a reductive environment of L-ascorbic acid. Characterisation of rGOA was performed by Fourier transform infrared, scanning electron microscope, transmission electron microscopy, nitrogen adsorption-desorption, Raman spectroscopy and X-ray diffraction. The developed rGOA had a measured density of 20.39 ± 5.28 mg/cm3, specific surface area of 132.19 m2/g, cumulative pore volume of 0.5388 cm3/g and point of zero charge of 6.3. A study on the simultaneous interactions of independent factors by response surface methodology suggested dosage and initial concentration as the dominant parameters influencing the adsorption of diclofenac. The highest diclofenac adsorption capacity (596.71 mg/g) was achieved at the optimum conditions of 0.25 g/L dosage, 325 mg/L initial concentration, 200 rpm shaking speed and 30 °C temperature. The adsorption equilibrium data were best fitted to the Freundlich model with correlation coefficient (R2) varying from 0.9500 to 0.9802. The adsorption kinetic data were best correlated to the pseudo-first-order model with R2 ranging from 0.8467 to 0.9621. Thermodynamic analysis showed that the process was spontaneous (∆G = − 7.19 to − 0.48 kJ/mol) and exothermic (∆H = − 12.82 to − 2.17 kJ/mol). This research concluded that rGOA is a very promising adsorbent for the remediation of water polluted by diclofenac.
•3D graphene aerogel was assembled by chemical reduction and freeze drying.•Optimisation by response surface methodology yielded highest q of 596.71 mg/g.•Optimum states: 0.25 g/L dosage, 325 mg/L concentration, 200 rpm shaking, 30 °C.•Adsorption equilibrium was best described by the Freundlich model.•Adsorption kinetic was best fitted to the pseudofirst-order kinetic model.
Catalytic pyrolysis of pine wood was carried out using H+ZSM-5 in a hydrogen environment. The first objective of this study was to investigate the effect of hydrogen pressure on catalytic pyrolysis ...using H+ZSM-5. The study found that there was no increase in the aromatic hydrocarbons as the hydrogen pressure increased. The second objective of this study was to incorporate a hydrogenation effect in addition to catalytic-cracking during pyrolysis so that the amount of hydrocarbons in the bio-oil could be increased. The effect of hydrogen pressure on the Mo-impregnated catalyst was investigated in pine wood pyrolysis. The Mo/ZSM-5 catalyst was not as active as H+ZSM-5 in lower pressures (100–300 psi); however, at 400 psi, Mo/ZSM-5 gave more hydrocarbons than H+ZSM-5 did. A significant increase in aromatic hydrocarbons was found when the H+ZSM-5 catalysts were impregnated with metals (Ni, Co, Mo, and Pt) as compared to just the zeolite at 400 psi. On average, 42.5 wt.% of biomass carbon was converted into hydrocarbons. Aromatic selectivity of major hydrocarbons was almost the same during hydrocatalytic pyrolysis of pine wood at 400 psi in the presence of all metal-impregnated H+ZSM-5 catalysts.
Direct application of bio-oil from fast pyrolysis as a fuel has remained a challenge due to its undesirable attributes such as low heating value, high viscosity, high corrosiveness and storage ...instability. Solvent addition is a simple method for circumventing these disadvantages to allow further processing and storage. In this work, computer-aided molecular design tools were developed to design optimal solvents to upgrade bio-oil whilst having low environmental impact. Firstly, target solvent requirements were translated into measurable physical properties. As different property prediction models consist different levels of structural information, molecular signature descriptor was used as a common platform to formulate the design problem. Because of the differences in the required structural information of different property prediction models, signatures of different heights were needed in formulating the design problem. Due to the combinatorial nature of higher-order signatures, the complexity of a computer-aided molecular design problem increases with the height of signatures. Thus, a multi-stage framework was developed by developing consistency rules that restrict the number of higher-order signatures. Finally, phase stability analysis was conducted to evaluate the stability of the solvent-oil blend. As a result, optimal solvents that improve the solvent-oil blend properties while displaying low environmental impact were identified.
Energy from biomass is increasingly gaining attention amidst the environmental challenges of coal and fossil fuels. This study investigated the effects of inert gases (N2, CO2, and N2/CO2) on ...intermediate pyrolysis and product properties from Bambara Groundnut Shells (BGS) (shells from an underutilized crop, which has high nutritional values). N2/CO2 atmosphere roughly represents flue gas. The results showed that the inert gases did not significantly affect the yields of bio-oil, biochar, and syngas. The pH of bio-oil ranged from 5.2–5.8, indicating the minimum presence of acids in bio-oil. The CHNS analysis showed that all bio-oil and biochar had their carbon content within 50.04–60.49 wt.%. The FESEM resulted in a wide range of pore sizes in biochar produced in an N2/CO2 atmosphere. The GC-MS (Gas Chromatography-Mass Spectrometry) analysis revealed the presence of compounds which can be categorized as alkene, acid, benzene derivatives, ketone, phenol derivatives, alcohol, aldehyde, alkyl, and ester. However, the presence of N2/CO2 gas favored alcohol and phenol production significantly.
•Two-stage RSM optimization on slow pyrolysis and Pb2+ adsorption was successful.•Optimum pyrolysis at 30mLmin−1 N2 flow, 10°Cmin−1 heat rate, 500°C, 30min.•Optimum adsorption at 200mgL−1 ...concentration, 0.3g dosage, 60min, pH 3.02.•Adsorption equilibrium was best represented by Freundlich model.•Kinetic was well described by both pseudo first-order and second-order models.
This research investigated the removal of lead (Pb2+) by a novel biochar derived from palm oil sludge (POS-char) by slow pyrolysis. Multistage optimizations with central composite design were carried out to firstly optimize pyrolysis parameters to produce the best POS-char for Pb2+ removal and secondly to optimize adsorption conditions for the highest removal of Pb2+. The optimum pyrolysis parameters were nitrogen flowrateof30mLmin−1, heating rateof10°Cmin−1, temperatureof500°C and timeof30min. The optimum Pb2+ adsorption conditions were concentrationof200mgL−1, timeof60min, dosageof0.3g and pH of 3.02. The various functional groups within POS-char played a vital role in Pb2+ uptake. Regeneration was demonstrated to be feasible using hydrochloric acid. Adsorption equilibrium was best described by Freundlich model. At low concentration range, adsorption kinetic obeyed pseudo-first-order model, but at high concentration range, it followed pseudo-second-order model. Overall, the results highlighted that POS-char is an effective adsorbent for Pb2+ removal.
Bio-oil a carbon based liquid fuel from fast pyrolysis of biomass, can bring prospective changes in the renewable energy field gradually. However, the bio-oil ought to be upgraded since it possesses ...several negative attributes such as high corrosiveness, high acidity, and high content of water. Catalytic pyrolysis and co-pyrolysis are able to improve some of the properties of bio-oil during production. The fast pyrolysis of palm kernel shell (PKS) produces acidic bio-oil whereas the fast pyrolysis of palm oil sludge (POS) liberates basic bio-oil. Therefore, current study investigated the fast co-pyrolysis of PKS with POS at different blend ratios (10, 20, 35 and 50 wt% POS with PKS) with the aim to produce bio-oil with improved pH. The corresponding blends were pyrolyzed at 507 ± 13 °C in a fixed bed reactor. As the amount of POS in the blends increased from 0 to 100 wt%, a negative synergistic effect (SP) was observed and so a decrease in bio-oil yield. The observation was attributed to the presence of AAEMs found in POS. The total acid number (TAN) of bio-oils decreased with increasing POS ratio in the blends as well. At PKS to POS mass ratio of 50:50, the pH value of the bio-oil produced was 4.6 ± 0.1. Based on the yield and physical properties of bio-oil, the blend with 20 wt% of POS was chosen as the desired ratio as it yielded 40.8 ± 3.7 wt% of bio-oil with a slight negative synergistic effect (SP) of 3.26.
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