Carbon Resources Conversion最新文献

Biomass, as the exclusive and abundant organic resources, is considered to be the promising renewable resource. Carboxylic acids are one of the many compounds that can be obtained from raw biomass. Decarboxylation of carboxylic acids into fuels and chemicals via electrochemical method at mild reaction condition has been studied for many years. The (non-)Kolbe reaction, one of the oldest organic electrochemical reactions, is the decarboxylation of carboxylic acids to produce alkanes, alcohols, esters, etc. And electrode materials influence the production of electrocatalytic decarboxylation products from carboxylic acids. Therefore, this work mainly reviews the recent advances in applications of anodic materials for (non-)Kolbe electrocatalytic decarboxylation of carboxylic acids. It discusses the reaction mechanism of (non-) Kolbe electrolytic reaction, and the electrocatalytic oxidation of carboxylic acid using different electrodes and electrolytic systems to synthesize fuels and chemicals. Also, various types of electrode catalysts, such as Pt-based catalysts, C-based catalysts, and other catalysts, are introduced in detail. Finally, the challenges and future trends of the (non-)Kolbe reaction of carboxylic acids are presented. This review found that platinum-based electrocatalysts proved to be the most promising catalysts at present. And in recent years, a variety of synthesis methods have been developed to synthesize small size and high-performance noble metal based amorphous catalysts. Another approach is to study catalysts without platinum electricity, such as Ru, Ir, Ti and carbon materials. The review is helpful in understanding and know the anodic materials and their application in (non-)Kolbe electrocatalytic decarboxylation of carboxylic acids for the readers.

This study focused on green-synthesized magnetite/carbon dots nanocomposites (GS-Fe₃O₄/Cdots) utilizing Moringa oleifera leaf extract and watermelon peel waste for rapid degradation of methylene blue (MB) dye. Co-precipitation and hydrothermal method were used to synthesize GS-Fe₃O₄ and Cdots, respectively. In addition, the sonication method was used to link Cdots on Fe₃O₄ surface. X-ray diffraction spectrum of GS-Fe₃O₄/Cdots inform the cubic inverse spinel and has crystallite size in the range of 10.1–7.2 nm. The crystallite size also decreased with the increase of Cdots concentration. The transmission electron microscope showed the most uniform size of nanocomposites at around 13.4 nm. The functional group of Fe-O was detected on the nanocomposites, proof that Fe₃O₄ still exists after fabrication. The presence of C = C, C-O, and C-O-C also indicates the existence of Cdots on the surface of Fe₃O₄. The addition of Cdots affected the saturation magnetization and coercivity value in the range of 29.2 – 38.3 emu/g and 59–65 Oe, respectively, which showed a good magnetic properties. As an organic dye, MB was used for a photocatalytic process under UV irradiation. The degradation efficiency was raised to 98% for 30 min photocatalytic process. The magnetically separable capability makes nanocomposites could be recycled and reused three times with high degradation. Furthermore, GS-Fe₃O₄/Cdots potential as a low-cost and environmentally friendly reusable photocatalyst for rapid wastewater degradation.

Hydrogen, a green energy carrier, is one of the most promising energy sources. However, it is currently mainly produced from depleting fossil fuels with high carbon emissions, which has serious negative effects on the economy and environment. To address this issue, sustainable hydrogen production from bio-energy with carbon capture and storage (HyBECCS) is an ideal technology to reduce global carbon emissions while meeting energy demand. This review presents an overview of the latest progress in alkaline thermal treatment (ATT) of biomass for hydrogen production with carbon storage, especially focusing on the technical characteristics and related challenges from an industrial application perspective. Additionally, the roles of alkali and catalyst in the ATT process are critically discussed, and several aspects that have great influences on the ATT process, such as biomass types, reaction parameters, and reactors, are expounded. Finally, the potential solutions to the general challenges and obstacles to the future industrial-scale application of ATT of biomass for hydrogen production are proposed.

In this work, to efficiently utilize waste fruit and low-rank coal for the hydrogen (H₂)-rich syngas production, steam co-gasification of banana peel (BP) and brown coal (BC) was studied in a fixed-bed reactor. The results showed that the gasification rate of BC was highly enhanced after mixing it with BP and the obvious synergistic effect was observed in all investigated three mixing weight ratios (i.e., 1:1, 1:4, 4:1), resulting in a higher carbon conversion as well as a H₂-rich gas production yield for the co-gasification. However, the extent of promotion by synergistic effect was affected by the reaction temperature, mixing ratio, and steam amount. It was found that the high potassium (K) species content in the BP provided the catalytic effect not only on water–gas shift reaction but also on tar reforming/cracking, thereby enhancing the gasification of BC. In addition, it is confirmed that steam should be an important factor to promote the synergistic effect and H₂-rich gas production.

Over the past few years, it is observed an increased interest for oleaginous microorganisms in the perspective to produce microbial oils of great commercial interest through the consumption of low/zero cost substrates. In this paper, the physiology of the fungus Umbelopsis isabellina growing on blends of glycerol and glucose was investigated. In all experiments the fungus completely consumed glucose and produced satisfactory quantities of biomass containing reserve lipids in high percentages. However, glycerol concentration in the growth medium was negatively correlated to glucose assimilation rate, mainly during the balanced-growth phase. Nevertheless, at high initial concentrations, glycerol was partially consumed and seemed to contribute positively to the suppression of lipid degradation. Following the discovery of this complex regulatory mechanism regarding glucose and glycerol co-assimilation, the activity of three key-enzymes namely aldolase, glycerol kinase and glycerol dehydrogenase, which are implicated in glycerol and glucose assimilation, was investigated. The experiments revealed a clear preference of the fungus for glucose over glycerol. On the other hand, storage polysaccharides are degraded instead of storage lipid at the late oleaginous phase for maintenance purpose. These new biochemical features will enable the design of appropriate growth media for the co-fermentation of these two substrates by U. isabellina with the aim to maximize lipid accumulation.

Carbon materials are widely used as catalysts in electrocatalytic oxidative (EO) degradation of wastewater due to their large specific surface area and low cost. Carbon materials can also be used as catalyst carriers for EO reactions due to their ease of functionalization with other heteroatoms and metals/metal oxides. To improve the catalytic activity and current efficiency of carbon materials, modifying the structural and physicochemical properties of conventional carbon materials are common improvement method. This review briefly outlines the recent research progress of carbon materials in EO for organic pollutants degradation. It also discusses the modification strategies and corresponding electrocatalytic properties of various carbon materials (carbon nanomaterials and porous carbon materials), and explores the EO mechanism. Finally, some summaries of the remaining challenges and future developments of carbon materials in the field of electrocatalysis are given.

Hydrogen has attracted widespread attention as a carbon-neutral energy source, but developing efficient and safe hydrogen storage technologies remains a huge challenge. Recently, liquid organic hydrogen carriers (LOHCs) technology has shown great potential for efficient and stable hydrogen storage and transport. This technology allows for safe and economical large-scale transoceanic transportation and long-cycle hydrogen storage. In particular, traditional organic hydrogen storage liquids are derived from nonrenewable fossil fuels through costly refining procedures, resulting in unavoidable environmental contamination. Biomass holds great promise for the preparation of LOHCs due to its unique carbon-balance properties and feasibility to manufacture aromatic and nitrogen-doped compounds. According to recent studies, almost 100% conversion and 92% yield of benzene could be obtained through advanced biomass conversion technologies, showing great potential in preparing biomass-based LOHCs. Overall, the present LOHCs systems and their unique applications are introduced in this review, and the technical paths are summarized. Furthermore, this paper provides an outlook on the future development of LOHCs technology, focusing on biomass-derived aromatic and N-doped compounds and their applications in hydrogen storage.

The present study investigates the active phases and the role of oxygen species in the toluene oxidation process over CuCeZrOx catalysts prepared with bacterial cellulose (BC), and compares them with nitric acid pickling CuCeZrOx-BC(H) and CeZrOx-BC catalysts. The investigation is carried out using in-situ DRIFT, O₂-TPD, H₂-TPR, XRD, and TEM techniques. Our findings suggest that dispersed CuO species on the catalyst surface, Cu-Ce-Zr-O, and Ce-Zr-O solid solutions are active for toluene oxidation over CuCeZrOx-BC, with corresponding activities decreasing successively. The in-situ DRIFT results demonstrate that gaseous oxygen facilitates the chemisorption of toluene on active oxygen species, forming benzoyl oxide species and partially oxidizing the absorbed intermediates to benzyl alcohol at room temperature. Furthermore, lattice oxygen is experimentally found to be involved in the deep oxidation of toluene, and the lattice oxygen present in dispersed CuO species dominates the toluene oxidation process over CuCeZrOx-BC.

Wasted tofu rich in protein was subject to hydrothermal pretreatment (HTPT) under different conditions (at 120, 140, 160 and 180 ℃; for 0, 30, 60 and 90 min) followed by biochemical methane potential (BMP) tests, and 140 ℃ and 0 min were found to be respectively the best temperature and duration for HTPT of tofu in terms of its biogas production. Under the under the optimal conditions (140 ℃, 0 min) the accumulative methane yield reached up to 510.9 mL·(gVS)^-1, which was 26.98 % higher than that without HTPT (402.3 mL·(gVS)^-1). The start-up process of continuous anerobic digestion (AD) of the tofu before and after hydrothermal treated (HT) at the optimal HTPT conditions (140 ℃, 0 min) was examined, to investigate and compare how their consequent AD responded to HTPT. It was found that, for start-up of continuous AD, the HT tofu delivered more balanced nutrients and thus led to more stable AD and quicker biogas production. Unavoidably, HTPT generated products refractory to biodegradation, to slightly decrease the total biogas production. During AD of HT tofu some weak ammonia-tolerant microbes, such as methylotrophic methanogens, survived and played indispensable roles. Analyses of living microbial community structure indicated that, some hydrolytic acidification bacteria intolerant to ammonia nitrogen (such as Proteobacteria) were always active and appeared at high proportion. The viable methylotrophic methanogens, e. g. RumEn M2, took obvious responsibilities in start-up of the AD for HT tofu.