Esterification of oleic acid by Cs-STA/ZK.
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•Cs exchanged silicotungstic acid supported on Zr-KIT-6 solid acid catalyst was synthesized by hydrothermal method.•Biodiesel produced from ...oleic acid and non-edible oils at a higher conversion rate of 99% and 98%.•The optimized reaction conditions are 120 °C, 1:27 oil – methanol molar ratio, 7 wt% catalyst loading and 5 h reaction time.
The development of solid acid catalyst with superior activity is of high interest for the production of biodiesel. In this study, an attempt was made to synthesize a novel solid acid catalyst based on mesoporous cesium exchanged tungstosilicic acid supported on Zr-KIT-6 (Cs-STA/ZK) and Sn-KIT-6 (Cs-STA/SnK). The catalysts were synthesized by hydrothermal method and characterized by various physicochemical techniques such as PXRD, BET, FTIR, SEM, TEM, XPS, and NH3-TPD. The reaction parameters were optimized using Cs-STA/ZK catalyst. The present investigation explores the production of biodiesel from oleic acid and non-edible oils such as castor oil, pongamia oil, and neem oil. Cs-STA/ZK catalyst exhibited the highest conversion in both esterification (99%) of oleic acid and transesterification (98%) of non-edible oils. Further, the recyclability and thermal stability of Cs-STA/ZK catalyst are investigated in detail.
Wound dressing is one of the most promising medical applications for chitin and chitosan. The adhesive nature of chitin and chitosan, together with their antifungal and bactericidal character, and ...their permeability to oxygen, is a very important property associated with the treatment of wounds and burns. Different derivatives of chitin and chitosan have been prepared for this purpose in the form of hydrogels, fibers, membranes, scaffolds and sponges. The purpose of this review is to take a closer look on the wound dressing applications of biomaterials based on chitin, chitosan and their derivatives in various forms in detail.
The fall armyworm Spodoptera frugiperda is a prime noctuid pest of maize on the American continents where it has remained confined despite occasional interceptions by European quarantine services in ...recent years. The pest has currently become a new invasive species in West and Central Africa where outbreaks were recorded for the first time in early 2016. The presence of at least two distinct haplotypes within samples collected on maize in Nigeria and São Tomé suggests multiple introductions into the African continent. Implications of this new threat to the maize crop in tropical Africa are briefly discussed.
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•Valorization of agro-industrial wastes has been comprehensively discussed.•Agro-industrial wastes are potential source for value creation.•Methodologies for obtaining products from ...agro-industrial wastes have been appraised.•Applications of LCA in agro-industrial circular bioeconomy have been uncovered.
Energy recovery from waste resources is a promising approach towards environmental consequences. In the prospect of environmental sustainability, utilization of agro-industrial waste residues as feedstock for biorefinery processes have gained widespread attention. In the agro-industry, various biomasses are exposed to different unit processes for offering value to various agro-industrial waste materials. Agro-industrial wastes can generate a substantial amount of valuable products such as fuels, chemicals, energy, electricity, and by-products. This paper reviews the methodologies for valorization of agro-industrial wastes and their exploitation for generation of renewable energy products. In addition, management of agro-industrial wastes and products from agro-industrial wastes have been elaborated. The waste biorefinery process using agro-industrial wastes does not only offer energy, it also offers environmentally sustainable modes, which address effective management of waste streams. This review aims to highlight the cascading use of biomass from agro-industrial wastes into the systemic approach for economic development.
Background & objectives: India has been reporting the cases of coronavirus disease 2019 (COVID-19) since January 30, 2020. The Indian Council of Medical Research (ICMR) formulated and established ...laboratory surveillance for COVID-19. In this study, an analysis of the surveillance data was done to describe the testing performance and descriptive epidemiology of COVID-19 cases by time, place and person.
Methods: The data were extracted from January 22 to April 30, 2020. The frequencies of testing performance were described over time and by place. We described cases by time (epidemic curve by date of specimen collection; seven-day moving average), place (area map) and person (attack rate by age, sex and contact status), and trends were represented along with public health measures and events.
Results: Between January 22 and April 30, 2020, a total of 1,021,518 individuals were tested for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Testing increased from about 250 individuals per day in the beginning of March to 50,000 specimens per day by the end of April 2020. Overall, 40,184 (3.9%) tests were reported positive. The proportion of positive cases was highest among symptomatic and asymptomatic contacts, 2-3-fold higher than among those with severe acute respiratory infection, or those with an international travel history or healthcare workers. The attack rate (per million) by age was highest among those aged 50-69 yr (63.3) and was lowest among those under 10 yr (6.1). The attack rate was higher among males (41.6) than females (24.3). The secondary attack rate was 6.0 per cent. Overall, 99.0 per cent of 736 districts reported testing and 71.1 per cent reported COVID-19 cases.
Interpretation & conclusions: The coverage and frequency of ICMR's laboratory surveillance for SARS-CoV-2 improved over time. COVID-19 was reported from most parts of India, and the attack rate was more among men and the elderly and common among close contacts. Analysis of the data indicates that for further insight, additional surveillance tools and strategies at the national and sub-national levels are needed.
Solar stills system design: A review Vishwanath Kumar, P.; Kumar, Anil; Prakash, Om ...
Renewable & sustainable energy reviews,
11/2015, Letnik:
51
Journal Article
Recenzirano
The fresh water requirement is tremendously increasing in the present society with all kinds of industrial and factory growth leading to more and more pollution of natural resources. On the other ...hand, there are many arid and desert regions in the world where there are less frequent rainfalls and ground water shortage. Most of the water bodies like rivers, lakes and so forth throughout the world are saline and brackish which are not suitable for domestic, irrigation and especially for drinking purposes. Solar desalination is proven to be eco-friendly and economical way of producing the fresh water to cater to the needs of rural population. Much research has already been done in the field of single effect passive and active solar stills which produces low quantity of fresh water. In recent years, attention has been focused on developing multi-effect solar stills coupling with flat plate and concentrating collectors in order to overcome the drawback of single effect stills. In the present study, a detailed review of all the solar stills both single and multi-effect type with passive and active configuration is presented. The present study aims at describing the design specifications and highlighting the merits and demerits of various solar stills upon which research has been done till recent past. Also a discussion on future scope is given with some recommendations in the field of solar stills improvement to economically produce sustainable potable water.
The main scope of this study was to compare the efficacy of different advanced oxidation processes (AOPs) combined with adsorption for treating secondary treated effluent of municipal wastewater in a ...continuous-lab-scale reactor. The results revealed enhanced removal of biological oxygen demand (BOD: C0: 14.1 and Ct: 0 mg L−1 (100%)), chemical oxygen demand (COD: C0: 40.5 and Ct: 4 mg L−1 (≤90%)), and total organic carbon (TOC: C0: 15.2 and Ct: 3.02–3.63 mg L−1 (∼80%)) by UV/PMS, O3/PMS, UV/O3/H2O2, and UV/O3/MnO2 processes followed by glass packed bed reactor (GPBR). Complete inactivation of the bacterial count was observed for all the studied processes. The GPBR showed the additional advantage of termination in the regrowth of bacterial count on the filtering medium. The gas-chromatography and mass spectrometry (GC-MS) analysis showed that AOP followed by adsorption reduced the concentrations of the by-products in the treated effluent. Overall, the synergy between AOP and adsorption improved the effluent quality to meet various indirect potable reuse (IPR) applications.
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•AOP/adsorption resulted in the simultaneous removal of organic contaminants (COD (≤90%)) and pathogens (∼100%).•UV/O3/MnO2/glass-packed bed reactor (GPBR) showed the best performance.•GPBR showed complete inactivation of the bacterial count.•Carbon-PBR showed regrowth of bacterial count on the filtering medium.•AOP/adsorption is the best option for indirect potable reuse applications.
Current wound dressings have disadvantages such as less flexibility, poor mechanical strength, lack of porosity, and a tendency for dressings to adhere onto the wound surface; in addition, a majority ...of the dressings did not possess antibacterial activity. Hydrogel-based wound dressings would be helpful to provide a cooling sensation and a moisture environment, as well as act as a barrier to microbes. To overcome these hassles, we have developed flexible and microporous chitosan hydrogel/nano zinc oxide composite bandages (CZBs) via the incorporation of zinc oxide nanoparticles (nZnO) into chitosan hydrogel. The prepared nanocomposite bandages were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). In addition, swelling, degradation, blood clotting, antibacterial, cytocompatibility, cell attachment on the material, and cell infiltration into the composite bandages were evaluated. The nanocomposite bandage showed enhanced swelling, blood clotting, and antibacterial activity. Cytocompatibility of the composite bandage has been analyzed in normal human dermal fibroblast cells. Cell attachment and infiltration studies showed that the cells were found attached to the nanocomposite bandages and penetrated into the interior. Furthermore, the in vivo evaluations in Sprague–Dawley rats revealed that these nanocomposite bandages enhanced the wound healing and helped for faster re-epithelialization and collagen deposition. The obtained data strongly encourage the use of these composite bandages for burn wounds, chronic wounds, and diabetic foot ulcers.
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•Production of biochar produced through pyrolysis of lignocellulosic biomass has been narrated.•The factors influencing pyrolytic conditions and pyrolytic conversion have been ...discussed.•Reviewed the modification of biochar and mechanism of pollutant adsorption using biochar.•Potential positive aspects of biochar applications towards pollutant removal are also discussed.
Thermochemical processing of biomass results in a producing char, a typical by-product. The char can be termed as biochar when specifically applied as a soil fertility enhancement. Biochar, when utilized efficiently, is basic for enhancing financial viability and also to maintain ecosystem. The properties of carbonized biomass rely upon raw materials (feedstock) and procedure conditions. Biochar shows an incredible potential to effectively handle water contaminants taking into consideration the wide accessibility of feedstock, suitable physical/chemical surface properties and low-cost. Pyrolysis technology for converting lignocellulosic biomass into biochar has emerged as a frontier research domain for the removal of pollutants. This review focused on production of biochar from various sources of lignocellulosic biomass (cellulose, hemicellulose and lignin) and its application in various fields such as agriculture, wastewater treatment process. Biochar is a significant resource however, its application require further examination of its properties and structure and techniques to alter those factors.
Release of pollutants due to inflating anthropogenic activities has a conspicuous effect on the environment. As water is uniquely vulnerable to pollution, water pollution control has received a ...considerable attention among the most critical environmental challenges. Diverse sources such as heavy metals, dyes, pathogenic and organic compounds lead to deterioration in water quality. Demand for the pollutant free water has created a greater concern in water treatment technologies. The pollutants can be mitigated through physical, chemical and biological methodologies thereby alleviating the health and environmental effects caused. Diverse technologies for wastewater treatment with an accentuation on pre-treatment of feedstock and post treatment are concisely summed up. Pollutants present in the water can be removed by processes some of which include filtration, reverse osmosis, degasification, sedimentation, flocculation, precipitation and adsorption. Membrane separation and adsorption methodologies utilized to control water pollution and are found to be more effective than conventional methods and established recovery processes. This audit relatively features different methodologies that show remarkable power of eliminating pollutants from wastewater. This review describes recent research development on wastewater treatment and its respective benefits/applications in field scale were discussed. Finally, the difficulties in the enhancement of treatment methodologies for pragmatic commercial application are recognized and the future viewpoints are introduced.
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•Effects of water pollution are highlighted.•Major toxic pollutants and their sources and effects have been discussed.•The various pollution control technologies have been explained.•Membrane separation and adsorption processes have been highlighted.•The research gap in the treatment methods are highlighted.
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