Incineration Method Research Articles

Hierarchical Approach to the Management of Drinking Water Sludge Generated from Alum-Based Treatment Processes

The management of drinking water treatment plant (DWTP) sludge is challenging for water treatment facilities. Previous studies reported mainly on handling sludge through landfilling, release into water bodies, discharge into wastewater treatment plants, onsite disposal, and incineration methods for the treatment of sludge. The limitations of these sludge-handling methods are well documented. This article focuses on the hierarchical approach as an alternative and comprehensive method for handling DWTP sludge. The core of hierarchical management streamlines the minimization of the generated DWTP sludge; treatment of DWTP sludge to reduce toxicity; changing of the physicochemical form of DWTP sludge; and finally, the reuse, recycling, and recovery of DWTP sludge. The premise is to achieve zero landfilling of DWTP sludge, establish a circular economy, generate job opportunities, and preserve the environment. Thus, this study also proposes two main technologies, which are gravity-based sludge separators for fractionating the sludge and photocatalytic membrane reactors (PMRs) as a technology for the treating and/or recovery of nutrients and minerals from DWTP sludge. Until the chemical deductive or minus approach becomes a reality in water treatment, the use of PMRs and gravity-based sludge separators will enhance the management of DWTP sludge when incorporated into the hierarchical approach.

Conversion of toxic pyrogenic products into syngas through catalytic pyrolysis of insulation material waste under the presence of CO2

Plastic-based insulation materials have been widely employed owing to their exceptional durability, cost-effectiveness, low weight, and low thermal conductivity. Nevertheless, the disposal of the insulation material waste (IMW) within construction waste and its recycling and recovery are challenging. Meanwhile, landfilling or incineration methods can release toxic chemicals into the environment. Consequently, the accumulation of IMW in construction waste has become a pressing environmental concern. To address this issue, this paper proposes a pyrolysis platform as a disposal management method for IMW that employs CO2 as a reactive medium. IMW composed of polystyrene in the form of extruded polystyrene underwent pyrolysis to yield pyrogenic products containing toxic chemicals. These toxic chemicals were subsequently transformed into syngas via homogeneous reactions with CO2 under certain thermal conditions and Ni/Al2O3 catalyst. This resulted in a significant reduction in the total peak areas of toxic substances in the pyrogenic oil compared with that obtained using N2 as a medium. Furthermore, the efficacy of CO2 was demonstrated to increase with an increase in the atmospheric concentration. This study implied that catalytic pyrolysis under CO2 conditions is a potential platform for converting toxic chemicals from IMW into syngas through homogeneous reactions with CO2.

Lodo do Curtimento de couro em Argamassa: Valorização Sustentável

Purpose: This study aims to investigate the valorisation of sludge from Leather Tannery Wastewater Treatment Plants (LTWWTP) by incorporating it into cement mortars. Theoretical framework: The substantial quantity of waste generated by industries coupled with the scarcity of natural resources calls for the analysis, development, and implementation of treatment methods to recover and reuse materials, thereby minimising the environmental impact of waste disposal. The leather tanning industry, a significant polluter due to its use of hazardous and heavy materials, requires sustainable solutions for waste management. One promising approach is the incorporation of waste into cementitious matrices. Method: Three scenarios were examined: low-moisture sludge, ash obtained via incineration, and wet oxidation. Test specimens were prepared with varying proportions of cement replacement (0, 3, 5, 7, and 10%), and their flexural and compressive strengths were evaluated. Additionally, chemical analyses were conducted to assess solubility. Results and Conclusion: The results indicate that sludge can be used in small proportions without compromising the mechanical strength of the mortar. Substituting 10% cement with ash using the INC-2 incineration method improved mortar quality, exhibiting a higher compressive strength of 41 MPa and minimal water absorption (3.28%). Research implications: Drawing from these promising findings, it can be confidently asserted that utilising WWTP sludge in mortar is a practical, eco-conscious solution for civil construction. Furthermore, it is a pivotal step towards addressing the challenge of hazardous sludge disposal. Originality/value: The findings from this research will contribute to sustainable waste management practices and pave the way for responsible and eco-friendly utilisation of industrial waste in cementitious materials, thus minimising environmental burdens.

Enhancing Solid Waste Management: The Advantages of Biodecomposers and Composting: Part 1

The relentless growth of the global population and economic expansion exacerbates the escalating challenge of Urban Solid Waste (USW) management. This paper explores the efficiency of bio-decomposers in treating organic waste, contrasting with traditional landfill and incineration methods, and emphasizes the social and environmental benefits of composting. The social and environmental advantages of converting waste to compost are scrutinized, underscoring the role of composting in promoting soil health and reducing greenhouse gas emissions. By highlighting specific case studies and providing data-driven results, this study aims to advocate for broader adoption of these technologies to improve waste management and sustainability, using the potential of bio-decomposers and composting as sustainable alternatives that can transform waste into valuable resources.

Preparation of phosphorus containing products by co-incineration of sludge ash and calcium-based additives: Focusing one-step and multi-step method

Due to the irreplaceable nature of phosphorus (P) in biological growth and the shortage of P rock, it is necessary to recover P from waste, such as sludge ash. P-containing products were prepared using sludge ash and calcium-based additives (CaCO3 and eggshell). In addition, the effects of different incineration methods (one-step method (OSM) and multi-step method (MSM)), additive doses, and incineration temperature on the P content and species in the products were investigated. The results indicated that as the dose of calcium-based additives increased, total P (TP) content in P-containing products reduced, apatite P (AP) content increased, non-apatite P (NAIP) content declined, and P solubility in citric acid content decreased. The amount of AP increased, NAIP reduced, and P solubility in citric acid decreased as the incineration temperature climbed. Although P in P-containing products prepared by OSM and MSM changed in a similar way at different additive doses and temperatures, P-containing products prepared by MSM had at least a 6.1% increase in P solubility in citric acid. Compared with OSM, MSM could save 10% of calcium-based additives when reaching the maximum AP value. Additionally, pure materials were employed to investigate how P species changed during the incineration procedure. The advantage of the MSM-prepared product over the OSM-prepared product may be explained by the high concentration of Ca3(PO4)2 and low concentration of amorphous calcium bound P (Ca-P). Overall, MSM is an effective method to reduce the dose of calcium-based additives and increase the bioavailability of P in P-containing products.

Catalytic Strategies for the Upcycling of Polyolefin Plastic Waste.

Chemical upgrading of waste plastics is currently one of the most important methods for addressing plastic pollution. In comparison to the current methods of incineration or landfill, chemical upgrading enables the utilization of carbon and hydrogen elements in waste plastics as resources. This process strongly relies on efficient catalysts and reaction systems. Through catalyst design, waste plastics can be converted into fuels or chemicals under the optimized reaction conditions, extending their life cycles. In this review, we systematically discuss various chemical conversion methods for polyolefin waste plastics, which account for a large proportion of waste plastics. We further explore the remaining challenges and future development trends in this field, including improving product value through product engineering and shifting research perspectives to exploring the tolerance of catalysts toward impurities in practical waste plastic waste rather than using pure plastic feedstock.

Studying the effectiveness of sewage sludge ash and its combination with natural pozzolans in controlling alkali–silica reaction

AbstractSewage sludge ash (SSA), obtained by the incineration of sewage sludge, which is a byproduct of water treatment, could be used as a cement replacement material (CSR) to promote sustainability. SSA characteristics differ due to its different sources, compositions, and incineration methods. On the other hand, extensive investigations have highlighted the CSRs' ability to control alkali–silica reaction (ASR) as a destructive phenomenon, threatening durability. Hence, this study was conducted in order to study the ability of SSA with two finenesses, three replacement levels, and also its ternaries with trass or pumice, as natural pozzolans, to control ASR. The utilized SSA did not meet the requirements of a pozzolan at either finenesses. The results revealed that despite the fact that SSA generally reduced ASR expansion significantly, it only managed to control ASR at 50% replacement level. This was true for both finenesses. Furthermore, ternaries improved resistance against ASR expansion significantly, providing the ability to control ASR at lower replacement levels of SSA. The Si/Ca ratio was the key reason of SSA's ability to control ASR as it contained 1.5 and 2.5 times more SiO2 and Al2O3 than Portland cement respectively, and about one third of its CaO. Scanning electron microscopey (SEM), energy dispersive spectroscopy (EDS), and mapping confirmed that the relative amounts of Si, Al, and Ca in the SSA was crucial.

Seasonal determination of proximate composition and essential elements in commercial fishes from Pakistan and human health risk assessment

The seasonal variability in proximate composition and essential elements demonstrates that the habitat and feeding habits of fish species play a vital role in energy transfer.
 We aimed to ascertain seasonal variability in the biochemical composition (protein, lipids, carbohydrates, ash, and moisture) and the amounts of Na, K, Ca, Mg, Mn, and Zn in the species Nemipterus japonicus, Epinephelus erythrurus, Nematalosa nasus, and Ilisha striatula inhabiting pelagic and demersal zones. We compared the nutritional profile of these fish species and their seasonal importance. The essential elements were detected by flame atomic absorption spectrometry and found in the following order: K > Na > Ca > Mg > Mn > Zn. To determine the proximate composition, we employed a number of methods: the Lowry method for protein analysis, the acid hydrolysis method for fat/lipid analysis, a formula for carbohydrates and moisture, and the incineration method for ash content.
 The spring inter-monsoon season showed the highest values for the essential elements in both pelagic and demersal species. However, the pelagic species had the highest biochemical composition levels during the southwest monsoon. The autumn intermonsoon had the lowest bio-profile for the fishes of both regimes.
 The summer season, which is not thought to be good for fish consumption, showed the highest biochemical composition levels in the pelagic fish. The nutritional profile of fish flesh can be affected by feeding habits, seasonal variation, and habitat.

Novel cost-effective oxygen-enriched melting method for MSWI fly ash

ABSTRACT Herein, a novel oxygen-enriched melting process for fly ash, which uses the biogas produced from the leachate of municipal solid waste incineration (MSWI) plants, is proposed to reduce the high cost of conventional fly ash – melting technology. The fly ash composition was estimated via X-ray fluorescence analysis; the six constituent elements detected in fly ash in the decreasing order of their content were calcium, chlorine, silicon, sulfur, sodium, and potassium. Based on literature and actual production data, the average yield of the leachate was 15% of the total waste entering the MSWI plants and the COD of leachate was 30,000–75,000 mg/L. The amount of biogas that can be used per ton of fly ash was calculated to be 62.0–157.0 m3. The analysis of melting thermal equilibrium revealed the amount of biogas required per ton of fly ash as 57.8 m3. The aforementioned research findings indicate that the biogas produced by MSWI plants can successfully meet the demands of the oxygen-enriched melting of fly ash produced in these plants. By establishing an oxygen-enriched-melting pilot platform, the pilot tests of melting were conducted on fly ash; the results revealed the good melting effects of fly ash. The X-ray diffraction analysis of the slag demonstrated that the content of the vitreous body met the technical requirements for glassy substances. Furthermore, the leaching toxicity test results revealed that heavy metals were well solidified in the slag. This study presents a novel fly ash – melting scheme for MSWI fly ash, namely, biogas oxygen-enriched melting strategy, which has the advantages of technical feasibility and cost-effectiveness. The proposed technique exhibits considerable prospects for widespread application in MSWI plants in China and can play an important role in the safe disposal of fly ash. Implications: In this paper, a low-cost melting method of municipal solid waste incineration(MSWI) fly ash is proposed. This method uses the biogas generated by MSWI plant itself as fuel for melting. Through research, it has been found that the production of biogas can meet the demand for fly ash melting. Adopting biogas as a molten fuel can significantly reduce the cost of melting, thereby significantly reducing the cost of fly ash melting. This study established a pilot scale platform for the melting of biogas and conducted pilot scale experiments on fly ash and additives. The experimental results showed that the melting system operated well and achieved the vitrification of fly ash. The leaching test results of the molten slag showed that heavy metals were well solidified in the slag. The research results can be extended to the MSWI plant for application, which can significantly reduce the cost of fly ash melting disposal, and has broad application prospects.

Economical Configuration of Oxygen-Enriched Air Production Process Using Polysulfone-Based Composite Membranes

Oxygen-enriched combustion technology is an emerging incineration method suitable for waste treatment. In this study, we investigated an economical modular configuration method for oxygen-enriched air production using gas separation membrane technology. Various module configurations were examined based on input pressure, gas temperature, sweep, and multistage module arrangement, and an optimal economically viable configuration was proposed. Using a polysulfone-based polymer membrane module, oxygen-enriched air with an oxygen concentration of 40–65% was produced. Even in cases of low input pressures achieved using a vacuum pump at the permeate side, oxygen-enriched air with concentrations >40% was achieved, with an approximately 20% increase in the permeation flow rate. As the permeation rate increased with increasing temperature, the oxygen recovery efficiency decreased. When the membrane area was increased, the corresponding increase in the input pressure did not result in a proportional increase in the permeation rate compared with single-module setups. Through multistage module arrangements, oxygen-enriched air with a maximum oxygen concentration of 66% was produced. By employing sweep that recirculated a portion of input air to the permeate side, the production of oxygen-enriched air was enhanced by approximately 38%. Therefore, the proposed process involving low input pressure, vacuum pumps, and sweeping was optimal for oxygen-enriched air production.

Potential reduction of greenhouse gas emissions from waste banks and 3R waste treatment facilities in Bandung City

The Indonesian government has established a 30% reduction by 2030 target for reducing GHG emissions, through the 3R (Reduce, Reuse, Recycle) approach. In the City of Bandung, various institutions are involved in waste handling and reduction. The objectives of this study were to determine the GHG emissions, resulting from household waste disposal at Sarimukti Landfill, without (scenario 1) and with (scenario 2) the utilisation of Waste Banks, 3R Waste Treatment Facility (TPS 3R), and an incinerator in a TPS 3R, at Ciwastra Market, as well as to estimate the GHG emissions, once Bandung City successfully achieves its waste reduction and waste management target in 2025, as stated in the Bandung Mayor Regulation No. 1426 of 2018, leveraging all existing facilities with the landfilling (scenario 3) and incineration (scenario 4) method. The calculations made were aligned with the Intergovernmental Panel on Climate Change (IPCC) 2019 Guidelines Tier 1. The findings of this study revealed that, in the first scenario, the GHG emissions amount to 185,271.934 tons of CO2eq. In the second scenario, the emissions amount to 150,423.096 tons of CO2eq. Consequently, the reduction in GHG emissions achieved is 34,848.847 tons CO2eq. In the third scenario, the emissions are 64,373.560 tons of CO2eq, while in the fourth scenario, GHG emissions are 70,001.973 tons of CO2eq. These findings highlight the substantial GHG emission reductions achievable through the implementation of waste management strategies. By adopting these approaches, it is possible to mitigate the environmental impact of waste disposal and contribute to the reduction of GHG emissions, well in tandem with the climate change mitigation goals.

Assessment of practices and awareness regarding the disposal of unwanted pharmaceutical products among community pharmacies: a cross-sectional study in Palestine

BackgroundThe improper disposal of pharmaceutical preparations substantially threatens human health and environmental safety. Pharmacists are responsible for properly disposing of unwanted medications and educating patients about how to do so themselves. This study aimed to assess community pharmacists’ knowledge, determine their views on how to dispose of unwanted pharmaceuticals, and assess the extent to which they realize that it is their responsibility to guide patients toward the safe disposal of expired medications.MethodsA descriptive cross-sectional study was conducted between December 2021 and April 2022 among 400 practicing pharmacists who were chosen to participate by random cluster sampling. Community pharmacists’ practices, awareness, and beliefs about disposing of unused drugs were evaluated. The Statistical Package for Social Sciences (IBM-SPSS) version 21 was used for data entry and analysis.ResultsOf 400 pharmacists, 348 stated that they did not participate in courses on the safe disposal of unwanted medications. Disposal of drugs in the garbage, an unsafe method, was very frequently recommended by pharmacists to patients, especially regarding inhalers, antibiotics, hormonal drugs, and solid and semisolid drugs. However, many pharmacists advised patients to return their hormonal, category B, and category C drugs to the pharmacy. A total of 61.3% of pharmacists agreed and 26% strongly agreed that unsafe disposal of drugs negatively affects the environment. A total of 54.3% of the participants agreed that improper disposal of antibiotics might be a reason for increased antimicrobial resistance, and 54.5% of them agreed that improper disposal of hormonal drugs might contribute to the development of certain cancers. A total of 80.3% of the participants perceived that most unwanted drugs in pharmacies were those returned from patients. A total of 97.3% of the participants supported establishing a drug disposal system, with 77.5% choosing to have the district health board responsible for funding this system. A total of 48.5% of the participants indicated that a lack of education and awareness on the issue of getting rid of unused drugs constitutes a challenge to the safe disposal of medicines, and 66% of them said that a lack of law enforcement constitutes another challenge. A total of 95.5% of the participants agreed or strongly agreed that good training for health sector workers and organizing workshops to develop knowledge on this subject would improve practices. A total of 93.3% supported distributing educational brochures, and 92.8% supported placing special containers in every pharmacy to collect unwanted drugs.ConclusionsMost pharmacists in our study returned drugs to manufacturing companies and stores, and few followed the correct methods of incineration and return of drugs to the Ministry of Health. Current data emphasize the issue of improper disposal of medicine in Palestine and the need for improved education among healthcare workers.

Synthesis of Fe-g-C3N4/FePc/BiVO4 Nanocomposites for Efficient Degradation of RhB

A novel photocatalyst comprising Fe-g-C3N4/FePc/BiVO4 heterostructure was synthesized using hydrothermal and muffle incineration methods. The synthesized catalyst was subjected to characterization using SEM, XRD, EDX, XPS, photocurrent response, and EIS analysis. Results showed that the Fe-g-C3N4/FePc/BiVO4 heterojunction composites significantly enhance the efficiency and stability of degradation of RhB. The unique advantages of the heterojunction composites include a wide range of light absorption and a small electron–hole complexation rate. Compared to pristine Fe-g-C3N4, FePc, and BiVO4, the photocatalytic activity and stability were significantly improved. The formation of a new structure of Fe-g-C3N4 and FePc and BiVO4 successfully adjusted the electron transfer route, resulting in more active sites and improving the efficiency of photogenerated charge separation. Furthermore, a possible mechanism for the photocatalytic degradation of RhB was proposed.

Utilizing Sewage Sludge Slag, a By-Product of the Circulating Fluidized Bed Combustion Process, to Efficiently Remove Copper from Aquatic Environment

Currently, one of the greatest threats to the aquatic environment is industrial wastewater containing heavy metals and other toxic substances. Hence, it seems necessary to search for ecological and cheap technologies for removing metals from wastewater. In this research, slag was used as waste obtained in the circulating fluidized bed combustion technology (CFBC), which is considered to be a modern, clean, and very effective method of incineration of municipal sewage sludge. The physicochemical properties of the waste material were characterized using selected analytical techniques. Next, the processes of adsorption of Cu(II) ions on slag in aqueous solutions were investigated. The results showed a high metal removal efficiency of 98.8% at pH 1.8 and slag dosage 5 g/L. Numerous studies have demonstrated that high process efficiency at a level of at least 90% is attainable. Based on the Langmuir equation, the maximum adsorption capacity was calculated to be 70.3 mg/g. Kinetic analysis revealed that the process fits better into the pseudo-second-order reaction model and the Freundlich isotherm. The intraparticle diffusion model was considered as a rate-controlling step for Cu(II) adsorption. In summary, the slag waste produced in the CFBC technology seems to be a highly effective adsorbent for potential use in adsorption processes to remove heavy metals from the aquatic environment. This solution is in line with the current European ‘zero waste’ strategy and the assumptions of a sustainable development economy.

A study of chloride pretreatment methods for enhancing strength of mortar by recycling Municipal Solid Waste Incineration (MSWI) bottom ash

This study explores four different ways (tap water, deionized water, sodium chloride, and seawater) as the pretreatment methods of Municipal Solid Waste Incineration (MSWI) bottom ash used in mortar. After incorporation of the bottom ash as partial replacement of fine aggregate, the mixtures were evaluated for compressive strength, heat of hydration, chloride content and shrinkage performance. The results reveal that all pretreated samples have comparable compressive strength at early age (day-7) and higher compressive strength at later age (day-120). Meanwhile, the pretreatment in tap water and deionized water can slightly reduce the chloride content, whereas the other two pretreatment methods induce extra chloride ions into the mixtures. The correlation between the chloride content and the peak temperature indicates the acceleration effect of chloride ions during hydration. In addition, all the specimens with pretreated MSWI aggregates have higher shrinkage regardless of pretreatment methods.

A Deep-Sea Bacterium Is Capable of Degrading Polyurethane.

Plastic wastes have been recognized as the most common and durable marine contaminants, which are not only found in the shallow water, but also on the sea floor. However, whether deep-sea microorganisms have evolved the capability of degrading plastic remains elusive. In this study, a deep-sea bacterium Bacillus velezensis GUIA was found to be capable of degrading waterborne polyurethane. Transcriptomic analysis showed that the supplement of waterborne polyurethane upregulated the expression of many genes related to spore germination, indicating that the presence of plastic had effects on the growth of strain GUIA. In addition, the supplement of waterborne polyurethane also evidently upregulated the expressions of many genes encoding lipase, protease, and oxidoreductase. Liquid chromatography-mass spectrometry (LC-MS) results showed that potential enzymes responsible for plastic degradation in strain GUIA were identified as oxidoreductase, protease, and lipase, which was consistent with the transcriptomic analysis. In combination of in vitro expression and degradation assays as well as Fourier transform infrared (FTIR) analysis, we demonstrated that the oxidoreductase Oxr-1 of strain GUIA was the key degradation enzyme toward waterborne polyurethane. Moreover, the oxidoreductase Oxr-1 was also shown to degrade the biodegradable polybutylene adipate terephthalate (PBAT) film indicating its wide application potential. IMPORTANCE The widespread and indiscriminate disposal of plastics inevitably leads to environmental pollution. The secondary pollution by current landfill and incineration methods causes serious damage to the atmosphere, land, and rivers. Therefore, microbial degradation is an ideal way to solve plastic pollution. Recently, the marine environment is becoming a hot spot to screen microorganisms possessing potential plastic degradation capabilities. In this study, a deep-sea Bacillus strain was shown to degrade both waterborne polyurethane and biodegradable PBAT film. The FAD-binding oxidoreductase Oxr-1 was demonstrated to be the key enzyme mediating plastic degradation. Our study not only provided a good candidate for developing bio-products toward plastic degradation but also paved a way to investigate the carbon cycle mediated by plastic degradation in deep-sea microorganisms.

Why have we not yet solved the challenge of plastic degradation by biological means?

The invention of fossil fuel-derived plastics changed and reshaped society for the better; however, their mass production has created an unprecedented accumulation of waste and an environmental crisis. Scientists are searching for better ways to reduce plastic waste than the current methods of mechanical recycling and incineration, which are only partial solutions. Biological means of breaking down plastics have been investigated as alternatives, with studies mostly focusing on using microorganisms to biologically degrade sturdy plastics like polyethylene (PE). Unfortunately, after a few decades of research, biodegradation by microorganisms has not provided the hoped-for results. Recent studies suggest that insects could provide a new avenue for investigation into biotechnological tools, with the discovery of enzymes that can oxidize untreated PE. But how can insects provide a solution that could potentially make a difference? And how can biotechnology revolutionize the plastic industry to stop ongoing/increasing contamination?

Solid Waste Treatment Using Multi-Criteria Decision Support Methods Case Study Lattakia City

Lattakia city faces many problems related to the mismanagement of solid waste, as the disposal process is limited to the random Al-Bassa landfill without treatment. Therefore, solid waste management poses a special challenge to decision-makers by choosing the appropriate tool that supports strategic decisions in choosing municipal solid waste treatment methods and evaluating their management systems. As the human is primarily responsible for the formation of waste, this study aims to measure the degree of environmental awareness in the Lattakia Governorate from the point of view of the research sample members and to discuss the effect of the studied variables (place of residence, educational level, gender, age, and professional status) on the level of environmental awareness. Data were collected and analyzed using the SPSS.21 statistical package. This study also presents a methodology to find the optimal scenario for solid waste treatment using the hierarchical analysis method represented by Expert Choice 11.1. The study found that there is an environmental awareness about the danger of the increasing percentage of environmental pollution and the presence of a social willingness to contribute to solid waste management, such as household sorting and working in voluntary associations. Environmental awareness is spreading throughout the province, but more attention is paid to the environment in the countryside than in the city. It was also found that environmental awareness is linked to the cultural level, and it was equal between males and females. The study also provided the optimal treatment method for solid waste according to the theory of hierarchical analysis, where the biogas production method ranked first with a rate of 35.5%, followed by the composting production method with 22.6%, the recycling method with 17.4%, followed by the incineration method by 15%. The sanitary landfill method ranked last, with 9.5%.

Evolution of Lewis acidity by mechanochemical and fluorination treatment of silicon carbide as novel catalyst for dehydrofluorination reactions

Transforming potent greenhouse gasses, hydrofluorocarbons (HFCs) to hydrofluoroolefins (HFOs) is an environmentally friendly and low energy input route compared with traditional incineration method. During the conversion process, Lewis acidity of the catalysts play a vital role in the activity. Here, inspired by the fluorinated metal oxide, a novel nonmetallic catalyst SiC was fabricated via sequentially mechanochemical treatment and fluorination. With series characterizations, it demonstrated that on the super surface of SiC, there are thin layers of graphite, COOH species, SiO2 and Si4C4-xO2 substrates. Through the mechanochemical treatment, the layers of graphite, COOH species and partial SiO2 could be grinded off. Hence, the exposed SiO2 residue could be removed via the fluorination by HFC-152a and HF forming volatile SiF4. At the same time, the transition layer, Si4C4-xO2 was fluorinated to Si4C4-xF2 accompanied with enhanced Lewis acidity. As a result, the activity of the treated SiC was significantly superior than the unmilled SiC. These findings provide a feasible way to develop the catalytic performances of nonmetallic catalysts for the dehydrofluorination.

Comparative characteristics of the emissions control during the operation of passenger trains

The trend in the development of railway transport also includes the solution of such an important environmental, technological, sanitary and, to some extent, aesthetic problem as the transfer of all operated mainline passenger trains to environmentally friendly toilet complexes (EFTC). For the disposal of EFTC waste, a system has been created for the disposal of fecal waste in parking lots, which are then transported by sewage disposal machines and dumped into general treatment facilities. At the moment, as one of the possible options for industrial waste disposal of EFTC, wastewater sludge incineration plants are being considered. The method of waste incineration reduces the time, labor and financial costs of waste turnover, and taking into account the epidemiological risks of fecal waste, it has high development prospects. This article discusses similar combustion processes using the example of technologies implemented at wastewater sludge incineration plants, emissions from enterprises and the processes of formation of pollutants. And also, within the framework of this work, a comparative analysis of the control of emissions of pollutants from the combustion of sewage sludge into the atmosphere in the Russian Federation and in the EU, countries were carried out.