Preparation of Pyrrhotite from Ammonium Jarosite and Estimation of Activation Energy in Reducing Atmosphere

Author(s):  
Xiaoling Ma ◽  
Hongbin Tan ◽  
Faqin Dong ◽  
Bowen Li ◽  
Jinfeng Liu ◽  
...  

Abstract Ammonium jarosite sediment is a by-product of hydrometallurgical process used to extract zinc metal, which, which contains heavy metal ions and raises severe environmental concerns The transformation of jarosite sediment into high-value-added sulfide products through simple processing is a cost-effective and efficient strategy to overcome environmental and waste management issues. Herein, the influence of sulfur on thermal decomposition of ammonium jarosite is investigated in reducing atmosphere. The results reveal that the presence of sulfur promoted the decomposition of ammonium jarosite and szomolnokite and iron oxide phases have been observed after being heat treated at 300 °C. Moreover, after heat treatment at 700 °C, the decomposition of jarosite/sulfur mixture resulted in the formation of pyrrhotite phase, which can be used as a raw material for sulfuric acid production. Lastly, the activation energy of pyrrhotite formation has been estimated by using KAS equation and found to be 216.2 kJ/mol in reducing atmosphere.

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Manuel Nieto-Domínguez ◽  
José Alberto Martínez-Fernández ◽  
Beatriz Fernández de Toro ◽  
Juan A. Méndez-Líter ◽  
Francisco Javier Cañada ◽  
...  

Abstract Background Currently, industrial societies are seeking for green alternatives to conventional chemical synthesis. This demand has merged with the efforts to convert lignocellulosic biomass into value-added products. In this context, xylan, as one of main components of lignocellulose, has emerged as a raw material with high potential for advancing towards a sustainable economy. Results In this study, the recombinant endoxylanase rXynM from the ascomycete Talaromyces amestolkiae has been heterologously expressed in Pichia pastoris and used as one of the catalysts of an enzyme cascade developed to synthesize the antiproliferative 2-(6-hydroxynaphthyl) β-d-xylopyranoside, by transglycosylation of 2,6-dihydroxynaphthalene. The approach combines the use of two fungal xylanolytic enzymes, rXynM and the β-xylosidase rBxTW1 from the same fungus, with the cost-effective substrate xylan. The reaction conditions for the cascade were optimized by a Central Composite Design. Maximal productions of 0.59 and 0.38 g/L were reached using beechwood xylan and birchwood xylan, respectively. For comparison, xylans from other sources were tested in the same reaction, suggesting that a specific optimization is required for each xylan variety. The results obtained using this enzyme cascade and xylan were similar or better to those previously reported for a single catalyst and xylobiose, an expensive sugar donor. Conclusions Beechwood and birchwood xylan, two polysaccharides easily available from biomass, were used in a novel enzyme cascade to synthetize an antiproliferative agent. The approach represents a green alternative to the conventional chemical synthesis of 2-(6-hydroxynaphthyl) β-d-xylopyranoside using a cost-effective substrate. The work highlights the role of xylan as a raw material for producing value-added products and the potential of fungal xylanolytic enzymes in the biomass conversion.


2019 ◽  
Vol 70 (4) ◽  
pp. 359-367
Author(s):  
Masoud Shafie ◽  
Hamid Zarea-Hosseinabadi

This study was performed to use date palm rachis, as a low value bio-waste, in the manufacture of a high value added eco-friendly structural composite lumber. Taguchi design of experiments was applied to analyse the effect of raw material and product parameters on the mechanical properties of laminated strand lumber from date palm rachis. The results indicate that the composite exhibits similar or superior strength properties compared to solid lumber and engineered products from wood or other lignocellulosic material for building sector. Taguchi design of experiments was assessed as a powerful and cost effective technique to obtain optimal levels for maximizing the mechanical properties of the environmentally-friendly composite. Maximum values for the mechanical properties of date palm rachis-based LSL were obtained from a combination of 20 mm product thickness, 10 % resin content, 4mm strand thickness, and 850 kg/m3 product density. Product thickness with an 81.3 % contribution and strand thickness with an 80 % contribution have the highest effects on the flatwise stiffness and compression strength perpendicular to grain, respectively.


2021 ◽  
Vol 9 ◽  
Author(s):  
Marco Marchese ◽  
Marta Gandiglio ◽  
Andrea Lanzini

In a mature circular economy model of carbon material, no fossil compound is extracted from the underground. Hence, the C1 molecule from non-fossil sources such as biogas, biomass, or carbon dioxide captured from the air represents the raw material to produce various value-added products through carbon capture and utilization routes. Accordingly, the present work investigates the utilization of the full potential of biogas and digestate waste streams derived from anaerobic digestion processes available at the European level to generate synthetic Fischer–Tropsch products focusing on the wax fraction. This study estimates a total amount of available carbon dioxide of 33.9 MtCO2/y from the two above-mentioned sources. Of this potential, 10.95 MtCO2/y is ready-to-use as separated CO2 from operating biogas-upgrading plants. Similarly, the total amount of ready-to-use wet digestate corresponds to 29.1 Mtdig/y. Moreover, the potential out-take of Fischer–Tropsch feedstock was evaluated based on process model results. Utilizing the full biogas plants’ carbon potential available in Europe, a total of 10.1 Mt/h of Fischer–Tropsch fuels and 3.86 Mt/h of Fischer–Tropsch waxes can be produced, covering up to 79% of the global wax demand. Utilizing only the streams derived from biomethane plants (installed in Europe), 136 ton/h of FT liquids and 48 ton/h of FT wax can be generated, corresponding to about 8% of the global wax demand. Finally, optimal locations for cost-effective Fischer–Tropsch wax production were also identified.


2016 ◽  
Vol 9 (1) ◽  
pp. 80-95
Author(s):  
Agus Sudibyo ◽  
Sardjono Sardjono

Crude palm oil (CPO)is the richest natural plant source of carotenoids in terms of retinol (pro-vitamin A) equivalent, whereas palm oil mill effluent (POME) is generated from palm oil industry that contains oil and carotenes that used to be treated before discharge. Carotenoids are importance in animals and humans for the purpose of the enhancement of immune response, conversion of vitamin A and scavenging of oxygen radicals. This component has different nutritional  functions and benefits to humaan health. The growing interest in the other natural sources of beta-carotene and growing awareness to prevent pollution has stimulated the industrial use of CPO and POME as a raw material for carotenoids extraction. Various technologies of extraction and separation have been developed in order to recover of carotenoids.This article reports on various technologies that have been developed in order to recover of carotenoids from being destroyed in commercial refining of palm oil and effects of some various treatments on the extraction end separation for carotenoid from palm oil and carotenoids concentration. Principally, there are different technologies, and there is one some future which is the use of solvent. Solvent plays important role  in the most technologiest, however the problem of solvents which are used is that they posses potentiaal fire health and environmental hazards. Hence selection of the  most safe, environmentally friendly and cost effective solvent is important to design of alternative extraction methods.Chemical molecular product design is one of the methods that are becoming more popular nowadays for finding solvent with the desired properties prior to experimental testing.ABSTRAKMinyak sawit kasar merupakan sumber karotenoid terkaya yang berasal dari tanaman sawit sebagai senyawa yang sama dengan retinol atau pro-vitamin A; sedangkan limbah pengolahan minyak sawit dihasilkan dari industri pengolahan minyak sawit yang berisi minyak dan karotene yang perlu diberi perlakuan terlebih dahulu sebelum dibuang. Karotenoid merupakan bahan penting yang diperlukan pada hewan dan manusia guna memperkuat tanggapan terhadap kekebalan, konversi ke vitamin A dan penangkapan gugus oksigen radikal. Dengan berkembangnya ketertarikan dalam mencari beta-karotene yang bersumber dari alam lain dan meningkatnya kesadaran untuk mencegah adanya pencemaran lingkungan, maka mendorong suatu industri untuk menggunakan CPO dan POME sebagai bahan baku untuk diekstrak karotenoidnya. Berbagai macam teknologi guna mengekstrak dan memisahkan karotenoid telah dikembangkan untuk mendapatkan kembali karotenoidnya. Makalah ini melaporkan dan membahas berbagai jenis teknologi yang telah dikembangkan guna mendapatkan kembali senyawa karotenoid dari kerusakan di dalam proses pemurnian minyak sawit secara komersial dan pengaruh beberapa perlakuan terhadap ekstrasi dan pemisahan karotenoid dari minyak sawit dan konsentrasi karotenoidnya. Pada prinsipnya, berbagai teknologi yang digunakan untuk mengekstrak dan memisahkan karotenoid terdapat perbedaan, dan terdapat salah satu teknologi yang digunakan untuk esktrasi dan pemisahan karotenoid adalah menggunakan bahan pelarut. Pelarut yang digunakan mempunyai peranan yang penting dalam teknologi ekstrasi; namun pelarut yang digunakan untuk mengekstrak tersebut mempunyai persoalan karena berpotensi mengganggu kesehatan dan membahayakan cemaran lingkungan. Oleh karena itu, pemilihan jenis teknologi yang aman, ramah terhadap lingkungan dan biaya yang efektif untuk penggunaan pelarut merupakan hal penting sebelum dilakukan desain metode/teknologi alternatif untuk esktrasi karotenoid. Pola produk molekuler kimia merupakan salah satu metode yang saat ini menjadi lebih populer untuk mencari pelarut dengan sifat-sifat yang dikehendaki sebelum diujicobakan. Kata kunci :    karotenoid, ekstrasi, pemisahan, teknologi, minyak sawit kasar, limbah industri pengolahan sawit.


2018 ◽  
Vol 27 (4) ◽  
pp. 096369351802700 ◽  
Author(s):  
Mehmet Önal ◽  
Gökdeniz Neşer

Glass reinforced polyester (GRP), as a thermoset polymer composites, dominates boat building industry with its several advantages such as high strength/weight ratio, cohesiveness, good resistance to environment. However, proper recovering and recycling of GRP boats is became a current environmental requirement that should be met by the related industry. In this study, to propose in a cost effective and environmentally friendly way, Life Cycle Assessment (LCA) has been carried out for six scenarios include two moulding methods (namely Hand Lay-up Method, HLM and Vacuum Infusion Method, VIM) and three End-of-Life (EoL) alternatives(namely Extruding, Incineration and Landfill) for a recreational boat's GRP hulls. A case study from raw materials purchasing phase to disposal/recycling stages has been established taking 11 m length GRP boat hull as the functional unit. Analysis show that in the production phase, the impacts are mainly due to the use of energy (electricity), transport and raw material manufacture. Largest differences between the methods considered (HLM and VIM) can be observed in the factors of marine aquatic ecotoxicity and eutrophication while the closest ones are abiotic depletion, ozon layer depletion and photochemical oxidation. The environmental impact of VIM is much higher than HLM due to its higher energy consumption while vacuum infusion method has lower risk than hand lay-up method in terms of occupational health by using less raw material (resin) in a closed mold. In the comparison of the three EoL techniques, the mechanical way of recycling (granule extruding) shows better environmental impacts except terrestrial ecotoxicity, photochemical oxidation and acidification. Among the EoL alternatives, landfill has the highest environmental impacts except ‘global warming potential’ and ‘human toxicity’ which are the highest in extrusion. The main cause of the impacts of landfill is the transportation needs between the EoL boats and the licenced landfill site. Although it has the higher impact on human toxicity, incineration is the second cleaner alternative of EoL techniques considered in this study. In fact that the similar trend has been observed both in production and EoL phases of the boat. It is obvious that using much more renewable energy mix and greener transportation alternative can reduce the overall impact of the all phases considerably.


2020 ◽  
Vol 9 (1) ◽  
pp. 55
Author(s):  
María Florencia Eberhardt ◽  
José Matías Irazoqui ◽  
Ariel Fernando Amadio

Stabilization ponds are a common treatment technology for wastewater generated by dairy industries. Large proportions of cheese whey are thrown into these ponds, creating an environmental problem because of the large volume produced and the high biological and chemical oxygen demands. Due to its composition, mainly lactose and proteins, it can be considered as a raw material for value-added products, through physicochemical or enzymatic treatments. β-Galactosidases (EC 3.2.1.23) are lactose modifying enzymes that can transform lactose in free monomers, glucose and galactose, or galactooligosacharides. Here, the identification of novel genes encoding β-galactosidases, identified via whole-genome shotgun sequencing of the metagenome of dairy industries stabilization ponds is reported. The genes were selected based on the conservation of catalytic domains, comparing against the CAZy database, and focusing on families with β-galactosidases activity (GH1, GH2 and GH42). A total of 394 candidate genes were found, all belonging to bacterial species. From these candidates, 12 were selected to be cloned and expressed. A total of six enzymes were expressed, and five cleaved efficiently ortho-nitrophenyl-β-galactoside and lactose. The activity levels of one of these novel β-galactosidase was higher than other enzymes reported from functional metagenomics screening and higher than the only enzyme reported from sequence-based metagenomics. A group of novel mesophilic β-galactosidases from diary stabilization ponds’ metagenomes was successfully identified, cloned and expressed. These novel enzymes provide alternatives for the production of value-added products from dairy industries’ by-products.


Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 899
Author(s):  
Djordje Mitrovic ◽  
Miguel Crespo Chacón ◽  
Aida Mérida García ◽  
Jorge García Morillo ◽  
Juan Antonio Rodríguez Diaz ◽  
...  

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO2 reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO2 emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO2 emissions reductions targets.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Gonzalo M. Figueroa-Torres ◽  
Jon K. Pittman ◽  
Constantinos Theodoropoulos

Abstract Background The production of microalgal biofuels, despite their sustainable and renowned potential, is not yet cost-effective compared to current conventional fuel technologies. However, the biorefinery concept increases the prospects of microalgal biomass as an economically viable feedstock suitable for the co-production of multiple biofuels along with value-added chemicals. To integrate biofuels production within the framework of a microalgae biorefinery, it is not only necessary to exploit multi-product platforms, but also to identify optimal microalgal cultivation strategies maximising the microalgal metabolites from which biofuels are obtained: starch and lipids. Whilst nutrient limitation is widely known for increasing starch and lipid formation, this cultivation strategy can greatly reduce microalgal growth. This work presents an optimisation framework combining predictive modelling and experimental methodologies to effectively simulate and predict microalgal growth dynamics and identify optimal cultivation strategies. Results Microalgal cultivation strategies for maximised starch and lipid formation were successfully established by developing a multi-parametric kinetic model suitable for the prediction of mixotrophic microalgal growth dynamics co-limited by nitrogen and phosphorus. The model’s high predictive capacity was experimentally validated against various datasets obtained from laboratory-scale cultures of Chlamydomonas reinhardtii CCAP 11/32C subject to different initial nutrient regimes. The identified model-based optimal cultivation strategies were further validated experimentally and yielded significant increases in starch (+ 270%) and lipid (+ 74%) production against a non-optimised strategy. Conclusions The optimised microalgal cultivation scenarios for maximised starch and lipids, as identified by the kinetic model presented here, highlight the benefits of exploiting modelling frameworks as optimisation tools that facilitate the development and commercialisation of microalgae-to-fuel technologies.


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