Environmental Progress & Sustainable Energy最新文献

Naturally occurring xanthan gum (XG) has much commercial importance because of its excellent physicochemical, eco-friendly, and non-toxic properties. It is used in various applications like protein extraction, wastewater treatment, tissue engineering, drug delivery, food packaging, and so forth. XG is a natural material, and it has some limitations related to the mechanical stress, thermal stability, and hydration. To overcome the limitation, XG can be modified by adding third component or modification of operation for specific applications. XG can be modified by physical, genetically, enzymatically, or chemical processes. Revamped XG also enhances the efficiency toward adsorbing toxic metal ions and organics from synthetic or industrial effluents. The emphasis of present review article is to address the structural characteristics along with the focus on the developing chemically modified XG like grafted, cross-linked, nanocomposites, and functionally modified biopolymer. However, this review commences thorough discussion on numerous ways of modifications, which can be attempted in XG structure, expanding its applications for heavy metal ion along with dye removal.

Immobilization of polyethyleneimine (PEI) on bamboo viscose fiber using epichlorohydrin (ECH) crosslinker (ABF-e-PEI) was employed to enhance the ability of dyeing with lac. The results from morphological observation, thermal degradation behavior, Fourier transform infrared (FTIR) analysis, x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) clearly revealed the success of PEI-immobilizing on fiber surface with no significant change in intrinsic properties of the fiber after modification. The modified fiber exhibited fast and efficient adsorption with the adsorption capacity >90 mg/g which was much higher than that of the unmodified adsorbent (did not exceed 10 mg/g). The results from kinetic and isotherm studies showed that the adsorption process conformed to the pseudo-second-order, intra-particle diffusion and Langmuir models. Adsorption temperatures have less effect to the adsorption performance of the modified adsorbent. Electrostatic ion-dipole interaction between protonated amines of PEI and negative charged sites of lac dye was the main proposed mechanism. Good resistance of color changes for ABF-e-PEI was confirmed by the color-fastness assessment (grade 4–5), suggesting efficient method of PEI-immobilizing using ECH crosslinker. The binding reaction of between amine groups of PEI and hydroxyl groups of the cellulosic fiber using ECH crosslinker can be expected to have a broad potential application in dyeing processes or pollution treatments due to its simple, cost-effective, flexible and efficient method.

As advanced oxidation processes (AOPs) is considered to be a highly effective approach for degrading organic pollutants, the simultaneous coagulation and oxidation process by the Fenton-like reaction of nanoscale zero-valent iron (NZVI) and hydrogen peroxide (H₂O₂) is investigated to eliminate the harmful cyanobacterium Microcystis aeruginosa in this study, and the process conditions are optimized using the central composite design of response surface methodology (RSM); in addition, the removal efficiency of M. aeruginosa (in terms of chlorophyll a, Chl a) and the verifications of the antioxidant abilities, as well as extracellular organic matters (EOM) and intracellular organic matters (IOM) are investigated under the optimized conditions. Results indicate that H₂O₂ concentration is the key factor affecting the Chl a removal efficiency, and the maximum Chl a removal reaches 98.10% under the optimized conditions: NZVI concentration 62.82 mg L⁻¹, H₂O₂ concentration 54.2 mmol L⁻¹, pH 4.38 and rotating speed 67 rpm. The high correlation coefficient (R² > 0.80) of analysis of variance (ANOVA) demonstrates the RSM model is extremely significant and suitable for experimental results. Moreover, the total organic carbon (TOC) and fluorescent substances (soluble cyanobacteria metabolic byproducts, aromatic proteins II, humic and fulvic acid-like compounds) for both EOM and IOM are enhanced removal. It is speculated the removal mechanisms of the Fenton-like process of NZVI/H₂O₂ for cyanobacterium belongs to the combined actions of the oxidation of Fe(II)/H₂O₂ and the coagulation of Fe(III), which destroy the defense system and result in the removal of M. aeruginosa.

The current research focuses on the impacts of pine oil injection and hydrogen induction separately with hemp oil methyl ester (HOME) in the single cylinder diesel engine in dual fuel-reactivity controlled compression ignition (DF-RCCI) combustion mode. The engine was tested under a DF-RCCI mode for the different energy shares of 10% pine oil with HOME (10P-HOME), 30% pine oil with HOME (30P-HOME), 3-lpm hydrogen with HOME (3-lpmH₂-HOME), and 6-lpm hydrogen with HOME (6-lpmH₂-HOME) separately at 345 °CA bTDC of low reactivity fuel (pine oil and hydrogen) and 23°C bTDC injection timing of high reactivity fuel (HOME). The results showed a higher Brake Thermal Efficiency (BTE) of 7.44%, 5.32%, 5.72%, and 2.46% for 6-lpmH₂-HOME, 3-lpmH₂-HOME, 30P-HOME, and 10P-HOME fuel shares, respectively, over the conventional diesel combustion (CDC) at full load. 30P-HOME, 3-lpmH₂-HOME, and 6-lpmH₂-HOME fuel combinations recorded 4.08% 4.42%, and 5.69% lower brake specific fuel consumption (BSFC), respectively, at full load. When comparing DF-RCCI combustion to CDC, an increase in the heat release rate (HRR) of 2.89%–26.50% and a rise in peak cylinder pressure of 0.77%–12.99% were observed. The 30P-HOME, 3-lpmH₂-HOME, and 6-lpmH₂-HOME emit less smoke in DF-RCCI combustion mode by 13.06%, 4.84%, and 7.26%, respectively at full load condition. When using 30P-HOME the exhaust gas temperature (EGT) decreased by 3.50% at full load condition. At part and full load conditions, the 30P-HOME fuel share reduced oxides of nitrogen (NO_X) emissions by 3.93% and 5.26%, respectively.

The exergy-based sustainability indices have been a cause of concern for gas turbine power plant as its performance is very sensitive to air temperature. Hence, the present study evaluates the impact of atmospheric air temperature on exergy sustainability and ecological function of a naphtha-based gas turbine power plant using EES. The outcome of the study shows that combustion chamber (CC_1) needs more attention compared with other components present, and it has least improvement potential as compared with other components. Further while carrying out parametric analysis with respect to ambient air, it was observed that for a 1.1°C increase in atmospheric air temperature a reduction in sustainability index about 0.66% was observed respectively, for GT_1. Thus, this study established that the power plant's exergy sustainability performance has a negative impact at high ambient air temperatures on exergy sustainability indices.

The content of selenium (Se) in most horticultural crops is low. To improve Se uptake in fruit trees, we investigated the impact of water extract derived from Nasturtium officinale R. Br. straw on the growth and Se uptake of peach seedlings under Se-enriched soil by a pot experiment. The water extract of N. officinale straw exhibited notable effects on various growth parameters and Se accumulation in peach seedlings, with the most significant outcomes observed at a 200-fold dilution. Specifically, the extract led to substantial enhancements in biomass, photosynthetic pigment content, antioxidant enzyme activity, and soluble protein content in peach seedlings. Remarkably, the 200-fold dilution of N. officinale straw extract resulted in a 60.78% increase in root biomass and a 31.26% increase in shoot biomass when compared to the control. Moreover, the water extract augmented the levels of total Se, inorganic Se, and organic Se, along with the activities of Se metabolism-related enzymes in peach seedlings. Among various tested dilutions, the 300-fold and 400-fold dilutions of N. officinale straw extract exhibited the highest total Se contents in roots and shoots, respectively, indicating increments of 97.26% and 44.08% over their respective controls. Additionally, correlation and gray relational analyses unveiled significant associations between peroxidase activity, soluble protein content, chlorophyll a content, chlorophyll a/b ratio, and the total shoot Se content. In conclusion, the water extract of N. officinale straw holds substantial potential for promoting the growth and Se uptake in peach seedlings, with the best concentration of 300-fold dilution.

In this paper, the role of periodate and persulfate as inorganic oxidants were studied in presence of ultraviolet radiation and titanium dioxide nanoparticles as a hybrid advanced oxidation photocatalytic processes for degradation and mineralization of the pirimicarb insecticide in aqueous media. The effects of several factors such as the ultraviolet irradiation, initial oxidant concentration, titanium dioxide nanoparticles dosage, and pH on the process performance were investigated. The process optimization was performed by the central composite design as a tools of response surface methodology for 30 mg L⁻¹ of the insecticide initial concentration at 25°C and 10 min of degradation process. A degradation efficiency of about 86% and 85% have been obtained for the persulfate and periodate processes, respectively, in the optimum conditions. The mineralization efficiency of the process using persulfate and periodate were about 35% and 46% after 60 min, respectively. The kinetic studies show that both processes follow a pseudo-first-order kinetic model and the rate constants were 0.1483 min⁻¹ for the persulfate and 0.1152 min⁻¹ for the periodate process. Generally, it can be concluded that this method is suitable for the degradation and mineralization of toxic aromatic compounds.

Selenium (Se) is an important trace element for human body, and the fruit Se source is one option for human Se supplementation. To increase grapevine uptake of Se, grape seedlings were transplanted in soils supplemented with sodium selenite, and the concentrations of 0, 1, 2, 4, and 6 g L⁻¹ chitosan were sprayed on grapevine seedling leaves. Next, the effects of chitosan on grapevine Se uptake were studied. The chitosan-based foliar application increased the biomass, photosynthetic pigment content, antioxidant enzyme activity, and soluble protein content of grapevine. Chitosan application also increased the total Se, inorganic Se, and organic Se contents in grapevine. However, while the root organic Se was increased, the shoot inorganic Se was decreased. Compared to the control, the concentrations of 1, 2, 4, and 6 g L⁻¹ chitosan increased the shoot total Se content by 9.29%, 12.39%, 17.70%, and 14.16%, respectively. Chitosan application also increased the nitrogen (N), phosphorus (P), and potassium (K) contents in grapevine. Moreover, correlation, gray relational, principal component, and cluster analyses revealed that the root total Se, shoot total N, and root total K contents were the top three indicators closely associated with the shoot total Se content. Therefore, foliar-based chitosan application on grape seedlings can promote the Se uptake in grapevine under sodium selenite supply, and 4 g L⁻¹ is the best concentration.

This study investigated the effects of different proportions of waste polyethylene (WP) and waste cooking oil (WCO) on the chemical and physical properties of the resulting co-pyrolysis oil produced in an indigenously developed laboratory-scale fixed bed batch-type reactor. The proportion of WCO was altered in increments of 10% from 10% to 90%, and correspondingly, the proportion of WP was adjusted from 90% to 10% (by weight). The highest liquid fuel yield, reaching 70.9% by weight, was achieved using a 40:60 ratio of WCO to WP (W40P60) at a constant heating rate of 12°C and a temperature of 500°C. The obtained fuel exhibits promising properties, including a high calorific value (max HHV around 45.63 MJ/kg) and other advantageous properties such as low viscosity, low oxygen and nitrogen content, and absence of sulfur. Fourier-transform infrared spectroscopy (FTIR) and gas chromatography–mass spectroscopy (GCMS) were examined on the resulting liquid fuel. The GC–MS spectra predominantly display alkanes, constituting approximately 41% by weight, and alkenes, making up roughly 20% by weight. These analyses revealed properties akin to commercial diesel, emphasizing the potential of waste cooking oil and waste polyethylene proportions in liquid diesel like fuel production.

A low-cost, high-performance alternative fuel to traditional fossil fuels is required due to rising energy demand, fossil fuel depletion, and rising prices. In this case, one of the green fuels could be synthesized using transesterification from waste-fried edible oil (WFEO). The current study deals with neat diesel (D100) and waste-fried edible oil biodiesel (B100) as the baseline fuels. By volume, a binary blend of 50% diesel and 50% WFEO biodiesel was prepared. The biodiesel/methanol/diesel mixture was considered a ternary blend under two different ternary ratios, such as B40M10D50 and B30M20D50, respectively. The fuel characterization and the rheological study were performed for all the fuel blends as per the ASTM standards. According to engine experimental results, the B30M20D50 blend has 25.42% higher brake thermal efficiency (BTE) than B100 but 3.4% lower than D100 at full load due to the higher methanol percentage. When compared with D100, adding 20% methanol to the ternary blend reduced brake-specific fuel consumption (BSFC) by 33.34%. Both ternary blends increased NOx emissions by 27.38% and 22.97% compared to D100 but decreased them by 14.23% and 18.68% compared to B100. Both ternary blends produced 0.4 and 0.36 kg/kWh at lower loads, while the D100 and B100 produced 0.46 and 0.42 kg/kWh. Finally, the entropy-weighted technique for order preference by similarity to the ideal solution (TOPSIS) multi-criteria decision-making method was used to determine the best blend for engine performance and emissions. The entropy-weighted TOPSIS technique likewise found that a B30M20D50 ternary blend with 75% loading had the lowest emissions and best performance.