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2.
Environ Res ; 251(Pt 2): 118617, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38467362

RESUMEN

This study aims to improve the quality of fuel with high calorific value namely Sfuel - a commercial high-quality refuse-derived fuel (RDF) from hazardous waste via modifying the process design and operating parameters of thermal conversion process. The study analyses key parameters of RDF quality, such as calorific value and heavy metal content, before and after process modifications based on the combination of experimental and simulation using Aspen Plus. In this study, the temperature and pressure of the simulation system are varied from 100 to 700 °C and from 1 to 5 bar, respectively. Findings indicate that there are a total of eleven heavy metals and 179 volatile compounds in the "Sfuels". The quality of the targeted product is greatly improved by the metal evaporation at high temperatures and pressures. However, the calorific value of RDF significantly decreases at 700 °C due to a large amount of the carbon content being evaporated. Although the carbon content at high temperatures is significantly lost, the heat from the vapour stream reactor outlet, which is reused to preheat the nitrogen gas stream supplied to the system, reduces energy consumption while improving the thermal conversion efficiency of the system. Besides, low pressure along with high temperature are not the optimal conditions for quality Sfuels improvement by thermal conversion. Results also indicate that electric heating is more economically efficient than natural gas heating.


Asunto(s)
Metales Pesados , Metales Pesados/análisis , Eliminación de Residuos/métodos , Simulación por Computador , Residuos Peligrosos/análisis , Calor
3.
Surgeon ; 22(4): 248-252, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38964980

RESUMEN

INTRODUCTION: Poor clinical waste management and its effect on the environment is an increasingly recognised concern for global healthcare systems. Approximately two thirds of waste produced in healthcare is from the operating theatre. In the Republic of Ireland, an estimated 580,977 tonnes of hazardous waste was produced in 2019. The cost of incineration of this hazardous waste is approximately €2,125 per tonne and €935 per tonne for sterilisation. Pollution from incineration is substantial and harmful. METHODS: A literature review was performed on the topic of hospital waste management, specifically looking at the Republic of Ireland. A comparison could then be drawn between Ireland, Europe and the United States of America. Observation of our current operating theatre environment and practices were carried out. DISCUSSION: An increased focus towards sustainability and reusable equipment means that there is potentially a decreased amount of waste for disposal, but an increase in the process of sterilisation. Approximately 66% of healthcare related waste is inappropriately contaminated, meaning that significant savings are possible if correct segregation and recycling were to occur. An increase in the amount of bins, identification labels above bins and education of staff results in an increased likelihood of successful segregation of waste. Clear and concise hospital guidelines of what is considered hazardous versus non-hazardous waste will decrease the amount of inappropriately disposed items.


Asunto(s)
Eliminación de Residuos Sanitarios , Quirófanos , Humanos , Irlanda , Eliminación de Residuos Sanitarios/normas , Administración de Residuos , Residuos Sanitarios , Estados Unidos , Residuos Peligrosos , Europa (Continente)
4.
J Environ Manage ; 367: 122036, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39094419

RESUMEN

Rapid global urbanization and economic growth have significantly increased solid waste volumes, with hazardous waste posing substantial health and environmental risks. Co-processing strategies for industrial solid and hazardous waste as alternative fuels highlight the importance of integrated waste management for energy and material recovery. This study identifies and characterizes solid and hazardous industrial wastes with high calorific values from various industrial processes at Nirma Industries Limited. Nine types of combustible industrial wastes were analyzed: discarded containers (W1), plastic waste (W2), spent ion exchange resins from RO plants (W3), sludge from effluent treatment in soap plants (W4), glycerine foot from soap plants (W5), rock wool puff material (W6), fiber-reinforced plastic waste (W7), spent activated carbon (W8), and spent cartridges from reverse osmosis plants (W9). Physical characterization, proximate and ultimate analysis, heavy metal concentration evaluation, and thermogravimetric analysis were conducted to assess their properties, revealing high calorific values exceeding 2500 kcal/kg. Notably, W1 and W2 exhibited the highest calorific values (∼10,870 kcal/kg), followed by W6 and W8 (∼6000 kcal/kg) and W9 (∼8727 kcal/kg). Safe heavy metal levels are safe, and high calorific values support the prospects of energy recovery and economic and environmental benefits, reducing landfill reliance and enhancing sustainable waste management.


Asunto(s)
Residuos Peligrosos , Residuos Peligrosos/análisis , Administración de Residuos/métodos , Residuos Sólidos/análisis , Industria Química , Metales Pesados/análisis
5.
J Environ Manage ; 350: 119567, 2024 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-38007927

RESUMEN

Dealing with the current defaults of environmental toxicity, heating, waste management, and economic crises, exploration of novel non-edible, toxic, and waste feedstock for renewable biodiesel synthesis is the need of the hour. The present study is concerned with Buxus papillosa with seeds oil concentration (45% w/w), a promising biodiesel feedstock encountering environmental defaults and waste management; in addition, this research performed simulation based-response surface methodology (RSM) for Buxus papillosa bio-diesel. Synthesis and application of novel Phyto-nanocatalyst bimetallic oxide with Buxus papillosa fruit capsule aqueous extract was advantageous during transesterification. Characterization of sodium/potassium oxide Phyto-nanocatalyst confirmed 23.5 nm nano-size and enhanced catalytic activity. Other characterizing tools are FTIR, DRS, XRD, Zeta potential, SEM, and EDX. Methyl ester formation was authenticated by FTIR, GC-MS, and NMR. A maximum 97% yield was obtained at optimized conditions i.e., methanol ratio to oil (8:1), catalyst amount (0.37 wt%), reaction duration (180 min), and temperature of 80 °C. The reusability of novel sodium/potassium oxide was checked for six reactions. Buxus papillosa fuel properties were within the international restrictions of fuel. The sulphur content of 0.00090% signified the environmental remedial nature of Buxus papillosa methyl esters and it is a highly recommendable species for biodiesel production at large scale due to a t huge number of seeds production and vast distribution.


Asunto(s)
Buxus , Administración de Residuos , Residuos Peligrosos , Biocombustibles/análisis , Ésteres , Catálisis , Sodio , Aceites de Plantas
6.
J Environ Manage ; 354: 120366, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38364544

RESUMEN

In recent years, illegal dumping of hazardous waste (IDHW) in China has become a recurring problem. Effective identification and exploration of the factors influencing illegal dumping are crucial for incident prevention and hazardous waste management, but its analysis has rarely been reported. Thus, this study focused on 568 cases of IDHW officially reported by the government. Through regular expressions, the categories of dumped wastes and the provinces where the incidents occurred were extracted. Furthermore, a comprehensive set of influencing factors was constructed by text mining for the case content and by the integration from the existing literature. On this basis, the unstructured and structured data were integrated using a Boolean dataset to respectively explore the association rules of influencing factors for the overall IDHW and for major waste categories, in conjunction with the extracted province information. Subsequently, a Bayesian network was constructed by utilizing the results of association rules mining and the key factors were identified through corresponding analysis. The findings of this study reveal a close connection between various influencing factors, with distinct key factors identified for different categories of hazardous waste. Among them, law-enforcement emerges as a crucial factor in most IDHW cases, while the factor of public monitoring for metallic hazardous waste and the factor of government supervision for distillation residue waste and other waste play a key role in their respective cases of illegal dumping. These findings offer a fresh research perspective for investigating the factors influencing IDHW and present helpful insights for developing effective strategies to prevent and control such incidents.


Asunto(s)
Residuos Peligrosos , Administración de Residuos , Teorema de Bayes , China , Administración de Residuos/métodos
7.
J Environ Manage ; 354: 120464, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38401504

RESUMEN

Brick kiln co-treatment is a novel industrial hazardous wastes (IHWs) utilization process. However, the effects of chlorine (Cl) in wastes on heavy metals (HMs) during this process are overlooked. This study investigated the stabilization/solidification (S/S) and volatilization, as well as long and short-term leaching, of HMs in Cl-containing bricks. The results indicated enhanced formations of stable mineral phases (NiFe2O4, Ni2SiO4, Cd3Al2Si3O12, CdSiO3, FeCr2O4, Cr2O3, CuFe2O4, and CuAl2O4) in bricks at a low sintering temperature (800 °C) due to the affinity between Cl and HMs. By comparing HM concentrations before and after sintering in bricks, the study observed that Cl's presence significantly elevated the volatilization rates for Cd and Cu by 30.8% and 14.2%, respectively. In contrast, the effect on volatilization for Ni and Cr was not significant. Additionally, utilizing the NEN 7375 method, the cumulative leaching rates of Ni, Cd, Cr, and Cu over a 64-day experiment under extremely acidic conditions were 0.22%, 7.18%, 0.01%, and 1.46%, respectively. Similarly, higher short-term leaching rates of Cd (4.03%) and Cu (5.73%) than those of Ni (0.94%) and Cr (0.08%) were observed. This finding might be attributed to the lower stability of the Cd and Cu solid phases under acidic environments compared to those of Ni and Cr. Surface wash-off, dissolution, and diffusion were the processes governing HM leaching from bricks. The 10-year projections revealed a minimal release of HMs during future extended leaching, implying the successful S/S of HMs. This study provides a reference for assessing the environmental impacts of brick kiln co-processing of Cl-containing IHWs.


Asunto(s)
Cloro , Metales Pesados , Cadmio , Residuos Peligrosos/análisis , Metales Pesados/análisis
8.
J Environ Manage ; 356: 120712, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38531127

RESUMEN

This review paper provides a comprehensive analysis of cement-based solidification and immobilisation of nuclear waste. It covers various aspects including mechanisms, formulations, testing and regulatory considerations. The paper begins by emphasizing the importance of nuclear waste management and the associated challenges. It explores the mechanisms and principles in cement-based solidification, with a particular focus on the interaction between cement and nuclear waste components. Different formulation considerations are discussed, encompassing factors such as cement types, the role of additives and modifiers. The review paper also examines testing and characterisation methods used to assess the physical, chemical and mechanical properties of solidified waste forms. Then the paper addresses the regulatory considerations and compliance requirements for cement-based solidification. The paper concludes by critically elaborating on the current challenges, emerging trends and future research needs in the field. Overall, this review paper offers a comprehensive overview of cement-based solidification, providing valuable insights for researchers, practitioners and regulatory bodies involved in nuclear waste management.


Asunto(s)
Residuos Radiactivos , Administración de Residuos , Administración de Residuos/métodos , Residuos Peligrosos
9.
J Environ Manage ; 353: 120148, 2024 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-38306856

RESUMEN

Arsenic-bearing neutralization (ABN) sludge is a classical hazardous waste commonly found in nonferrous metallurgy. However, the current storage of these hazardous wastes not only has to pay costly hazardous waste taxes but also poses significant risks to both the environment and human health. To address these issues and achieve the comprehensive utilization and minimization of ABN sludge, this study proposes a new combined process. The process involves selective reduction roasting, leaching, and carbonation, through which, the arsenate and gypsum in the ABN sludge were recovered in the form of As(s), high-purity CaCO3, and H2S. The selective reduction behaviors of arsenate and gypsum were investigated through thermodynamic analysis and roasting experiments. The results indicated that the 95.35 % arsenate and 96.55 % gypsum in the sludge were selectively reduced to As4(g) and CaS at 950 °C by carbothermic reduction. The As4(g) was condensed to As(s) and enriched in the dust (As, 96.78 wt %). In the leaching process, H2S gas was adopted to promote the leaching of CaS, and resulted in 97.41 % of CaS in the roasted product was selectively leached in the form of Ca(HS)2, leading to a 74.11 % reduction in the weight of the ABN sludge. Then, the Ca(HS)2 was subjected to capture CO2 for the separation of Ca2+ and S2-. The result depicted that 99.69 % of Ca2+ and 99.12 % of S2- were separated as high-purity (99.12 wt %) CaCO3 and H2S (24.89 vol %) by controlling the terminal carbonation pH to below 6.55. The generated H2S can be economically converted to sulfur by the Clause process. The whole process realized the comprehensive resource recovery and the minimization of the sludge, which provides an alternative solution for the clean treatment of hazardous ABN waste.


Asunto(s)
Arsénico , Humanos , Arsénico/análisis , Aguas del Alcantarillado , Arseniatos , Sulfato de Calcio , Residuos Peligrosos
10.
J Environ Manage ; 351: 119730, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38086123

RESUMEN

In this study, the behavior of heavy metal transformation during the co-thermal treatment of hazardous waste incineration fly ash (HWIFA) and Fe-containing hazardous waste (including hazardous waste incineration bottom slag (HWIBS) and electroplating sludge (ES)) was investigated. The findings demonstrated that such a treatment effectively reduced the static leaching toxicity of Cr and Pb. Moreover, when the treatment temperature exceeded 1000 °C, the co-thermal treated sample exhibited low concentrations of dynamically leached Cr, Pb, and Zn, indicating that these heavy metals were successful detoxified. Thermodynamic analyses and phase transformation results suggested that the formation of spinel and the gradual disappearance of chromium dioxide in the presence of Fe-containing hazardous wastes contributed to the solidification of chromium. Additionally, the efficient detoxification of Pb and Zn was attributed to their volatilization and entry into the liquid phase during the co-thermal treatment process. Therefore, this study sets an excellent example of the co-thermal treatment of hazardous wastes and the control of heavy metal pollution during the treatment process.


Asunto(s)
Metales Pesados , Eliminación de Residuos , Ceniza del Carbón , Eliminación de Residuos/métodos , Aguas del Alcantarillado/análisis , Residuos Peligrosos/análisis , Galvanoplastia , Plomo , Incineración/métodos , Metales Pesados/análisis , Residuos Sólidos/análisis , Carbono , Material Particulado/análisis
11.
Waste Manag Res ; 42(4): 344-351, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37277997

RESUMEN

Marine litter is a growing environmental problem for which fisheries-sourced waste remains poorly understood. In Peru, there is an ongoing challenge of waste management from the small-scale fisheries fleet given the lack of facilities to receive the variety of debris produced by fishers, which includes hazardous wastes such as batteries. In this study, onboard solid waste production was monitored daily by land-based observers upon landing at the port of Salaverry, Peru, from March to September 2017. The analysed small-scale gillnet and longline fishing fleets produced annually an estimated 11,260 kg of solid waste. Of particular concern is the production of single use plastics (3427 kg) and batteries (861 kg) due to their potential long-lasting impacts on the environment and challenges related to their proper disposal. A management plan for solid waste has been developed for Salaverry; therefore, a subsequent assessment was conducted in 2021-2022 of the behaviours and perceptions of fishers regarding the implementation of this plan. Most fishers (96%) reported disposing of their waste on land, except organic waste which is disposed of at sea. While fishers in Salaverry have become more conscious of the issues surrounding at-sea waste disposal and have an interest in better segregating and managing their waste, there remains a need for improved waste management and recycling protocols and procedures at the port to make this possible.


Asunto(s)
Eliminación de Residuos , Residuos Sólidos , Explotaciones Pesqueras , Perú , Residuos Peligrosos , Plásticos , Residuos
12.
Waste Manag Res ; 42(2): 95-110, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37313954

RESUMEN

Ayurveda hospitals generate biomedical wastes (BMW). However, details on composition, quantities and characteristics are very scarce, details which are important to formulate a proper waste management plan for subsequent implementation and continual improvement. Therefore, this article presents a mini review of the composition, quantities and characteristics of BMW generated from Ayurveda hospitals. Additionally, this article presents some best possible treatment and disposal procedures. Most of the information was gleaned from peer-reviewed journals, although some information was collected by the author and from grey literature available to the author; 70-99% (by wet weight) of the solid waste is non-hazardous; biodegradables contributing to 44-60% by wet weight due to more used Kizhi (medicinal bags for fomentation) and other medicinal/pharmaceutical wastes (excluding waste medicated oils, which is 12-15% of the liquid medicinal waste stream and are not readily biodegradable) largely derived from plants. The hazardous waste component includes infectious wastes, sharps, blood as pathological wastes (from Raktamoksha - bloodletting), heavy metal containing pharmaceutical wastes, chemical wastes and heavy metal rich wastes. Quantities of infectious wastes followed by sharps and blood form a major portion of hazardous wastes. Most of the infectious waste material contaminated with blood or other body fluids and sharps from Raktamoksha are very similar (appearance, moisture content and bulk density) to what is generated from hospitals practicing Western medicine. However, hospital-specific waste studies are required in future to better understand the sources, areas of generation, types, quantities and characteristics of BMW, and hence to formulate more accurate waste management plans.


Asunto(s)
Eliminación de Residuos Sanitarios , Metales Pesados , Eliminación de Residuos Sanitarios/métodos , Hospitales , Residuos Peligrosos , Sur de Asia , Residuos Sólidos , Preparaciones Farmacéuticas
13.
Environ Sci Technol ; 57(21): 8161-8173, 2023 05 30.
Artículo en Inglés | MEDLINE | ID: mdl-37192406

RESUMEN

The Basel Convention and prior studies mainly focused on the physical transboundary movements of hazardous waste (transporting waste from one region to another for cheaper disposal). Here, we take China, the world's largest waste producer, as an example and reveal the virtual hazardous waste flows in trade (outsourcing waste by importing waste-intensive products) by developing a multiregional input-output model. Our model characterizes the impact of international trade between China and 140 economies and China's interprovincial trade on hazardous waste generated by 161,599 Chinese enterprises. We find that, in 2015, virtual hazardous waste flows in China's trade reached 26.6 million tons (67% of the national total), of which 31% were generated during the production of goods that were ultimately consumed abroad. Trade-related production is much dirtier than locally consumed production, generating 26% more hazardous waste per unit of GDP. Under the impact of virtual flows, 40% of the waste-intensive production and relevant disposal duty is unequally concentrated in three Chinese provinces (including two least-developed ones, Qinghai and Xinjiang). Our findings imply the importance of expanding the scope of transboundary waste regulations and provide a quantitative basis for introducing consumer responsibilities. This may help relieve waste management burdens in less-developed "waste havens".


Asunto(s)
Residuos Peligrosos , Abastecimiento de Agua , Comercio , Internacionalidad , China
14.
Ecotoxicol Environ Saf ; 263: 115249, 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37441948

RESUMEN

Precisely predicting the amount of household hazardous waste (HHW) and classifying it intelligently is crucial for effective city management. Although data-driven models have the potential to address these problems, there have been few studies utilizing this approach for HHW prediction and classification due to the scarcity of available data. To address this, the current study employed the prophet model to forecast HHW quantities based on the Integration of Two Networks systems in Shanghai. HHW classification was performed using HVGGNet structures, which were based on VGG and transfer learning. To expedite the process of finding the optimal global learning rate, the method of cyclical learning rate was adopted, thus avoiding the need for repeated testing. Results showed that the average rate of HHW generation was 0.1 g/person/day, with the most significant waste categories being fluorescent lamps (30.6 %), paint barrels (26.1 %), medicine (26.2 %), battery (15.8 %), thermometer (0.03 %), and others (1.22 %). Recovering rare earth element (18.85 kg), Cd (3064.10 kg), Hg (15643.43 kg), Zn (14239.07 kg), Ag (11805.81 kg), Ni (4956.64 kg) and Li (1081.45 kg) from HHW can help avoid groundwater pollution, soil contamination and air pollution. HVGGNet-11 demonstrated 90.5 % precision and was deemed most suitable for HHW sorting. Furthermore, the prophet model predicted that HHW in Shanghai would increase from 794.43 t in 2020 to 2049.67 t in 2025.


Asunto(s)
Eliminación de Residuos , Administración de Residuos , Humanos , Eliminación de Residuos/métodos , Residuos Peligrosos/análisis , Productos Domésticos , China , Contaminación Ambiental/análisis , Administración de Residuos/métodos
15.
Risk Anal ; 43(9): 1811-1823, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-36464493

RESUMEN

Areas immediately adjacent to 16 of the first US national priority (NPL) hazardous waste sites that also had pre-superfund emergency actions were examined to measure local stigma. Four decades after their NPL designation, I found marked variation in these areas' social, public health and environmental attributes. About one-third of these small areas fit the stereotype of stressed areas with environmental injustice challenges. Yet, another one-third of these sites have better measurable outcomes than a combination of their host states and counties. For example, they have elevated levels of broadband access and their local jurisdictions are classified as safe and attractive to families. I conclude that long-term stigma around a Superfund site was limited by US EPA actions, as well as by progressive state and local governments, and community groups, in other words, contributions from parties at multiple geographical scales.


Asunto(s)
Residuos Peligrosos , Eliminación de Residuos , Estados Unidos , Humanos , Sustancias Peligrosas , Salud Pública , United States Environmental Protection Agency
16.
J Environ Manage ; 343: 118218, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37247551

RESUMEN

The spread of antimony from mine wastes to the environment represents a matter of great concern due to its adverse effects on impacted ecosystems. There is an urgent need for developing and adopting sustainable and inexpensive measures to deal with this type of wastes. In this study the Sb leaching behavior of mine waste rocks and mine tailings derived from the exploitation of Sb ore deposits was characterized using standard batch leaching tests (TCLP and EN-12457-4) and column leaching essays. Accordingly, these mine wastes were characterized as toxic (>0.6 mg Sb L-1) and not acceptable at hazardous waste landfills (>5 mg Sb kg-1), showing also an ongoing Sb release under prolonged leaching conditions. Two industrial by-products were evaluated as amendments to stabilize them, namely deferrisation sludge (DFS) and a by-product derived from the treatment of aluminum salt slags (BP-Al). Mine wastes were amended with different doses (0-25%) of DFS or BP-Al and the performance of these treatments was evaluated employing also batch and column leaching procedures. The effectiveness of DFS to immobilize Sb was much higher than that exhibited by BP-Al. Thus, treatments with 25% BP-Al showed Sb immobilization levels of approximately 33-53%, whereas treatments with 5 and 25% DFS already attained Sb immobilization levels up to approximately 80-90 and 90-99%, respectively. Mine tailings amended with 5% DFS and mine waste rocks amended with 25% DFS decreased their leachable Sb contents below the limit for non-hazardous waste landfill acceptance (<0.7 mg Sb kg-1). Likewise, these DFS treatments were able to revert their toxic characterization. Moreover, the 25% DFS treatment showed to be a long-lasting stabilizing system, efficient at least during a leaching period equivalent to 10-year rainfall with a great Sb leaching reduction (close to 98%). After this long-term leaching process, DFS-treated mine wastes kept their non-hazardous and non-toxic characterization. The amorphous Fe (oxyhydr)oxides composing DFS were responsible for the important Sb removal capacity showed by this by-product. Thus, when DFS was applied to mine wastes mobile Sb was importantly fixed as non-desorbable Sb, showing also a considerable Sb removal capacity in presence of strong competing anions such as phosphate. The application of DFS as amendment presents a great potential to be used as a sustainable long-term stabilizing system of Sb mine wastes.


Asunto(s)
Antimonio , Ecosistema , Residuos Peligrosos
17.
J Environ Manage ; 325(Pt B): 116586, 2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-36419310

RESUMEN

Tungsten residue waste (TRW), considered an environmental burden due to high content and excessive leaching toxicity of arsenic (As), are also secondary tungsten (W) resources. A novel method for simultaneous extraction of arsenic and tungsten from TRW via alkaline pressure oxidative leaching was proposed. The results show that As in the TRW mainly exists in the form of As coprecipitated with Mn(Ⅱ) oxides and FeAsS. In addition, As coprecipitated with Mn(Ⅱ) oxides and W are encapsulated in Fe, Mn oxides. The structure of Fe, Mn oxides with dense surface can be destroyed and the chemically stable arsenopyrite can be efficiently oxidized by oxygen in alkaline solutions. The leaching efficiency of As and S reached 97% and 99% at 80 min, respectively, while that of W reached 82% at 10 min. The leaching rate of As and S is controlled by diffusion with the apparent activation energies of 16.67 kJ/mol and 15.66 kJ/mol, respectively. Compared with TRW, the leaching toxicity of As in the leach residue decreased from 10.2 mg/L to only 0.071 mg/L. The new process suggests new possibilities for removal and recovery of As and W from TRW that will contribute to circular economy and environmental protection.


Asunto(s)
Arsénico , Tungsteno , Residuos Peligrosos , Oxidación-Reducción , Óxidos
18.
J Environ Manage ; 342: 118294, 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37295149

RESUMEN

Waste zinc-rich paint residue (WZPR) represents a typical hazardous waste containing both toxic organic substances and heavy metals. The extraction of Zn from WZPR by traditional direct bioleaching has been attracting attention owing to its eco-friendliness, energy conservation and low cost. However, a long bioleaching time and a low Zn release cast a shadow on the reputed bioleaching. To shorten the bioleaching time, the spent medium (SM) process was first used to free Zn from WZPR in this study. The results showed that the SM process had a much higher performance in Zn extraction. Zn removals of 100% and 44.2% (8.6 g/L and 15.2 g/L in the released concentration) were gained within 24 h under pulp densities of 2.0% and 8.0%, respectively, being over 1000 times of the release performance of Zn by previously reported direct bioleaching. On the one hand, the biogenic H+ in SM attacks ZnO to liberate Zn (Ⅱ) via quick acid dissolution. On the other hand, the biogenic Fe3+ not only highly oxidizes Zn0 in WZPR to generate and release Zn2+ but also intensely hydrolyzes to produce H+ to attack ZnO for further dissolution of Zn2+. Both biogenic H+ and Fe3+ contribute to over 90% of Zn extraction as the leading indirect bioleaching mechanism. Due to the high concentration of released Zn2+ and fewer impurity, the bioleachate was used to successfully produce high-purity ZnCO3/ZnO using a simple precipitation, thus achieving the high-value recycling of Zn in WZPR.


Asunto(s)
Metales Pesados , Óxido de Zinc , Zinc/química , Residuos Peligrosos
19.
J Environ Manage ; 344: 118470, 2023 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-37399626

RESUMEN

Sustainable valorization of tannery sludge (TS) is vital for achieving several sustainable development goals (SDGs) in the tannery industry. TS is considered a hazardous waste by-product posing a significant environmental challenge. However, TS can be utilized for energy or resource recovery by considering it as biomass and implementing the circular economy (CE) concept. Therefore, this study aims to develop an innovative DPSIR (Driver, Pressure, State, Impact, and Response) framework for promoting sustainable valorization of TS. Further, the study extends to quantify the importance of subjective DPSIR factors by offering interval-valued intuitionistic fuzzy number-based best worst method (IVIFN-BWM), which is relatively new in the literature and able to deal with the uncertainty, inconsistency, imprecise, and vagueness in the decision-making process. The study also investigates the most appropriate TS valorization technologies concerning identified DPSIR factors using a novel IVIFN-combined compromise solution (CoCoSo) approach. This research contributes to the literature by developing a comprehensive solution approach that combines the DPSIR framework, IVIFN-BWM, and IVIFN-CoCoSo method in addressing sustainability and resource recovery challenges for the tannery industry. The research findings highlight the potential of sustainable valorization of TS in reducing the waste amount and promoting sustainability and CE practices in the tannery industry. The findings indicated that response factors 'creation of national-level policies and awareness campaign' and 'facilitating financial support to adopt waste valorization technologies' received the highest priority among other DPSIR factors for managing and fostering sustainable valorization of TS. The IVIFN-CoCoSo analysis confirmed that the most promising TS valorization technology is 'gasification', which is followed by pyrolysis, anaerobic digestion, and incineration. The study's implications extend to policymakers, industrial practitioners, and researchers, who can leverage the research findings to develop more sustainable TS management practices in the tannery industry.


Asunto(s)
Residuos Peligrosos , Aguas del Alcantarillado , Incineración , Incertidumbre , Desarrollo Sostenible
20.
J Environ Manage ; 326(Pt A): 116674, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36410302

RESUMEN

Ferrochrome slag (FCS) is a by-product of ferrochrome industries and is produced during the extraction of ferrochrome from chromite ore. The chemical composition of FCS comprises of 27-33% SiO2, 15-25% Al2O3, 20-35% MgO, and 10-15% iron-chromium compounds. The high chromium content of FCS and the possibility of its leaching into the environment categorize FCS as hazardous waste material. For each ton of ferrochrome production, nearly 1.2-1.5 tons of FCS is generated, which becomes a significant challenge for the ferrochrome producers while managing this hazardous waste. Therefore, several research attempts have been made to observe the leaching characteristics of chromium (VI) in FCS, its stabilization, and subsequent potential utilization. The high mechanical properties of FCS have led many researchers worldwide to utilize it as a construction material. This review work has undertaken FCS's physical, chemical, and microstructural characteristics and its following utilization as a fine and coarse aggregate in producing green and sustainable concrete. Different methods of stabilizing chromium (VI), including the physical, chemical, and biological methods, are extensively discussed in this review. This article also accommodated FCS as a precursor material in geopolymer and alkali-activated binders. However, the compressive strength achieved with FCS as a binder in geopolymer is very low, and thus more studies are needed to establish the possibility of strength enhancement. The leaching aspects of geopolymers with FCS also need to be studied extensively for their successive application. Lastly, the conclusions and discussion of this study have keenly addressed the significant challenges to the safe utilization of FCS in construction applications. Also, it deliberates on how the emerging research on FCS, such as refractory, composites, and coating material, can be new avenues for its utilization without any potential threat to the environment.


Asunto(s)
Álcalis , Dióxido de Silicio , Cromo , Sustancias Peligrosas , Residuos Peligrosos
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