The world is facing environmental pollution and is in an alarming situation due to industrialization and urbanization. Especially, industrial wastewater discharge is causing serious pollution in the ...environment (water, soil, and air) and has become a challenge for researchers and scientists. Wastewater contains heavy metals like Cu, Ni, Cr, Pb, and Ar and causes toxicity in living beings and the environment. In this review, the sources of heavy metals and their toxicological effects on the environment have been reviewed. Various remediation techniques such as reverse osmosis, chemical precipitation, and ultrafiltration are being used for the treatment of wastewater, but still are limited in their efficiencies, residues, cost, and versatility. In this study, the most promising wastewater treatment technique, the physic-chemical technique, has been reviewed along with its working mechanism and efficiency. Further, the pros and cons of this technique and sub-techniques have also been reviewed to provide a basic understanding to beginners and a pathway to experts in the selection of better techniques.
The present study is concerned with evaluating the influence of various concentrations of Ag within Cu:Ag bimetallic nanoparticles developed for use as a promising anti-bacterial agent against ...antibiotic-resistant bacteria. Here, Cu:Ag bimetallic nanoparticles with various concentration ratios (2.5, 5.0, 7.5, and 10 wt%) of Ag in fixed amount of Cu labeled as 1:0.025, 1:0.050, 1:0.075, and 1:0.1 were synthesized using co-precipitation method with ammonium hydroxide and deionized water as solvent, polyvinyl pyrrolidone as a capping agent, and sodium borohydride and ascorbic acid as reducing agents. These formulated products were characterized through a variety of techniques. XRD confirmed phase purity and detected the presence of distinct fcc structures belonging to Cu and Ag phases. FTIR spectroscopy confirmed the presence of vibrational modes corresponding to various functional groups and recorded characteristic peak emanating from the bimetallic. UV–visible spectroscopy revealed reduction in band gap with increasing Ag content. SEM and HR-TEM micrographs revealed spherical morphology of Ag-doped Cu bimetallic with small and large scale agglomerations. The samples exhibited varying dimensions and interlayer spacing. Bactericidal action of synthesized Cu:Ag bimetallic NPs depicted statistically significant (
P
< 0.05) inhibition zones recorded for various concentrations of Ag dopant against
Staphylococcus aureus
(
S. aureus
)
, Escherichia coli
(
E. coli
)
,
and
Acinetobacter baumannii
(
A. baumannii
) ranging from (0.85–2.8 mm), (0.55–1.95 mm) and (0.65–1.85 mm), respectively. Broadly, Cu:Ag bimetallic NPs were found to be more potent against gram-positive compared with gram-negative. Molecular docking study of Ag–Cu bimetallic NPs was performed against
β
-lactamase which is a key enzyme of cell wall biosynthetic pathway from both
S. aureus
(Binding score: − 4.981 kcal/mol) and
A. bauminnii
(Binding score: − 4.013 kcal/mol). Similarly, binding interaction analysis against FabI belonging to fatty acid biosynthetic pathway from
A. bauminnii
(Binding score: − 3.385 kcal/mol) and
S. aureus
(Binding score: − 3.012 kcal/mol) along with FabH from
E. coli
(Binding score: − 4.372 kcal/mol) was undertaken. These theoretical computations indicate Cu-Ag bimetallic NPs as possible inhibitor of selected enzymes. It is suggested that exploring in vitro inhibition potential of these materials may open new avenues for antibiotic discovery.
High energy consumption, rapid increase in its demand and depletion of energy resources in the world are compelling the researchers for exploration of renewable energy resources in order to attain ...sustain development of nations. Many existing resources are being used to fulfil the current requirements. But these existing resources are also causing serious environmental pollution which is a very serious concern of the current era. Therefore, there is an immense need to think and produce environment friendly and sustainable renewable energy resources. Water, being abundant on Earth, is one of the most suitable sources of hydrogen energy. In this work the splitting of water and hydrogen production by different techniques, specially the promising photocatalysis technique, are discussed in detail. The water splitting and hydrogen production depend upon the properties of photocatalysts which rose from the nature, composition and other factors of photocatalysts. Therefore, this study discussed different materials like metal oxides, metal sulphides, nanocomposites, etc. which are used for photocatalytic hydrogen production. In addition, the pros and cons of the utilized materials are discussed to select the best class of materials for hydrogen production from water splitting. This review will help the beginners of this field to understand the basic mechanisms of different hydrogen production techniques along with their advantages and disadvantages. However, it will also help the field experts and industrialists to select the best class of materials for hydrogen evolution from water splitting.
Today’s world needs highly efficient systems that can fulfill the growing demand for energy. One of the promising solutions is the fuel cell. Solid oxide fuel cell (SOFC) is considered by many ...developed countries as an alternative solution of energy in near future. A lot of efforts have been made during last decade to make it commercial by reducing its cost and increasing its durability. Different materials, designs and fabrication technologies have been developed and tested to make it more cost effective and stable. This article is focused on the advancements made in the field of high temperature SOFC. High temperature SOFC does not need any precious catalyst for its operation, unlike in other types of fuel cell. Different conventional and innovative materials have been discussed along with properties and effects on the performance of SOFC’s components (electrolyte anode, cathode, interconnect and sealing materials). Advancements made in the field of cell and stack design are also explored along with hurdles coming in their fabrication and performance. This article also gives an overview of methods required for the fabrication of different components of SOFC. The flexibility of SOFC in terms fuel has also been discussed. Performance of the SOFC with varying combination of electrolyte, anode, cathode and fuel is also described in this article.
Lube oils are the viscous petroleum products used in automobiles to reduce the friction. The eventual fate of lube oil is either incineration or dumping off into ground, but these resources cannot be ...disposed off easily due to their libellous effects on environment. This article aims to study the regeneration of deteriorated oil and impact of regenerated oil on engine performance and engine emissions. The effectuality of regeneration is studied by comparing the results of the key parameters (specific gravity, viscosity, total acid number, flash point and ash contents) of regenerated oil with that of non-deteriorated and deteriorated oil. Engine performance and emissions for regenerated oil were compared with non-deteriorated and deteriorated oil. The brake power and torque increased by 4.1% and 4.6%, respectively, following the regeneration process. After re-refining of lube oil, specific gravity, flash point, kinematic viscosity, ash content and total acid number improved by 6.75%, 2.66%, 15.6%, 1.7% and 10.64%, respectively. In case of deteriorated oil, HC, NOx and CO increased by 23.6%, 42.2% and 11.8%, respectively. But after regeneration of oil, these emissions decreased as compared with deteriorated oil. It can be reasoned out that regeneration mends oil properties and has positive impact over engine performance and emissions.
Microbial fuel cell (MFC) technology is anticipated to be a practical alternative to the activated sludge technique for treating domestic and industrial effluents. The relevant literature mainly ...focuses on developing the systems and materials for maximum power output, whereas understanding the fundamental electrochemical characteristics is inadequate. This experimental study uses a double-chamber MFC having graphite electrodes and an anion-exchange membrane to investigate the electrochemical process limitations and the potential of bioelectricity generation and dairy effluent treatment. The results revealed an 81% reduction in the chemical oxygen demand (COD) in 10 days of cell operation, with an initial COD loading of 4520 mg/L. The third day recorded the highest open circuit voltage of 396 mV, and the maximum power density of 36.39 mW/m2 was achieved at a current density of 0.30 A/m2. The electrochemical impedance spectroscopy analysis disclosed that the activation polarization of the aerated cathode was the primary factor causing the cell’s resistance, followed by the ohmic and anodic activation overpotentials.
For evaluating the significance of renewable alternative fuels for optimized engine performance and lower emissions, methanol has been extensively utilized as a blend with gasoline in spark-ignition ...engines. However, rare attempts have been rendered to examine the consequence of methanol–gasoline fuel blends (M6, M12, and M18) on lubricant oil operating for a longer period in engines. The highest and least decrease of 9.62% and 6.68% in kinematic viscosity (KV) was observed for M0 and M18, respectively. However, the flash point (FP) of degraded lubricant oil for M6, M12, and M18 was 3%, 5%, and 7% higher than that of M0, respectively. Total acid number (TAN) and ash content of degraded lubricant oil for M18 were the highest among M0, M6, and M12. An inclusive optimization of engine performance, emissions, and lubricant oil properties has been made for various methanol–gasoline fuel blends at distinct operating conditions by employing the response surface methodology (RSM) technique. RSM-based optimization portrayed the composite desirability value of 0.73 for 2137.13 watt brake power (BP), 6.08 N-m torque, 0.37 kg/kwh brake-specific fuel consumption, 22.10% brake thermal efficiency, 4.02% carbon monoxide emission, 7.15% carbon dioxide emission, 134.12 ppm hydrocarbon emission, 517.02 ppm nitrogen oxides emission, 12.44 cst KV, 203.77°C FP, 2.23 mg/g KOH TAN, and 2.65%wt ash content as responses for fuel blend M8 at 3400 rpm and higher loading condition. RSM predicted results demonstrated significant compliance with empirical findings, with absolute percentage error (APE) below 5% for each response. However, the highest APE of 4.68% was obtained for FP owing to inefficient desirability as a consequence of manual testing. The least APE of 1.57% was obtained for torque because of the highest desirability. Overall, the RSM predicted results of the designed models are effective and viable. RSM technique was found to be effective for the optimization of the broader engine characteristics spectrum.
BaCe0.2Zr0.6Y0.2O3−δ (BCZY) perovskite electrolytes were synthesized for intermediate-temperature solid oxide fuel cell with a cost-effective and versatile co-precipitation method. The synthesized ...BCZY electrolytes were sintered at 900, 1000, and 1100 °C to observe the effects of low sintering temperature on the structural, morphological, thermal, and electrical properties of BCZY. All BCZY electrolytes materials exhibited a crystalline perovskite structure and were found to be thermally stable. The crystallinity and conductivity of BCZY electrolyte enhanced with increased sintering temperature, due to the grain growth. At the same time, secondary phases of carbonates were also observed for samples sintered at a temperature lower than 1100 °C. The BCZY sintered at 1100 °C exhibited a density >95%, and a power density of 350 mWcm−2 with open-circuit voltage 1.02 V at 650 °C was observed due its dense and airtight structure. Based on the current investigation, we suggest that the BaCe0.2Zr0.6Y0.2O3−δ perovskite electrolyte sintered at a temperature of 1100 °C is a suitable electrolyte for IT-SOFC.
Nanocomposites Samarium doped Ceria (SDC), Gadolinium doped Ceria (GDC), core shell SDC amorphous Na2CO3 (SDCC) and GDC amorphous Na2CO3 (GDCC) were synthesized using co-precipitation method and then ...compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs). The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC) and dual phase core shell (SDCC, GDCC) electrolyte materials. EDX analysis validated the presence of Sm and Gd in both single and dual phase electrolyte materials; also confirming the presence of amorphous Na2CO3 in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core shell GDC/amorphous Na2CO3 and SDC/ amorphous Na2CO3 nanocomposites using methane fuel. It is observed that dual phase core shell electrolytes materials (SDCC, GDCC) show better performance in low temperature range than their corresponding single phase electrolyte materials (SDC, GDC) with methane fuel.
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