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1.
Materials (Basel) ; 17(10)2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38793354

RESUMO

The co-processing of different wastes as fuels in the manufacture of cement clinker not only meets the objectives of a circular economy but also contributes to the reduction in CO2 emissions in the manufacture of Portland cement. However, waste used as alternative fuels, such as sludge or organic-rich residues, may contain naturally occurring radionuclides that can be concentrated during the combustion process. In this study, the presence of natural radionuclides (radioactive series of uranium, thorium, and 40K) and anthropogenic radionuclides (137Cs) in these wastes has been investigated by gamma spectrometry. Possible relationships between the radioactive content and the obtained chemical composition, determined by X-ray fluorescence, have also been studied by applying a principal component analysis (PCA). The results showed that the wastes with the highest radioactive content were sewage sludge with activity concentrations of 238U and 210Pb of 321 ± 38 Bq kg-1 and 110 ± 14 Bq kg-1, respectively. A correlation between radioactive content and Fe2O3 concentration was also observed. The annual effective dose rates to workers for the ashes estimated from the ash content ranged from 0.0033 mSv to 0.092 mSv and therefore do not pose a risk to workers as they are lower than the 1 mSv per year limit for the general public (DIRECTIVE 2013/59/EURATOM).

2.
Environ Pollut ; 356: 124260, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38815888

RESUMO

The advancement of co-processing solid wastes in coal-fired boilers is significant for waste recycling and contributes to the sustainable development of the coal-fired power industry. However, concerns over the emission of dioxins during co-processing have prompted a comprehensive investigation into the dioxin emission properties. In this study, the PCDD/F emission concentrations of seven coal-fired boilers, including three pulverized coal boilers and four circulating fluidized bed boilers were examined. The results indicate that co-processing solid wastes in coal-fired boilers did not lead to an increase in the mass concentration of dioxins in either the flue gas or solid samples, and the international toxic equivalents (I-TEQ) of dioxins in the flue gas complied with prevailing emission standards (0.1 ng I-TEQ/Nm3) in China, proving that coal-fired boilers co-processing would not raise the emission risk of dioxins. The types of waste during co-processing had minimal effect on the I-TEQ of dioxins. A significant proportion of PCDD/Fs was observed in the ash samples, while only 13.0-25.7% and 0.7-6.8% of dioxins were distributed in the boiler slag and the flue gas, respectively. The emission factor of dioxins under the blank conditions ranged from 0.009 to 0.327 ng I-TEQ/kg-coal, while it ranged from 0.015 to 0.129 ng I-TEQ/kg-(coal+waste) under the co-processing conditions. The reduction of emission factor under co-processing condition could be attributed to the significant decrease of dioxins I-TEQ.

3.
J Environ Manage ; 359: 120986, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38696849

RESUMO

The efficient, safe and eco-friendly disposal of the chromium-containing sludge (CCS) has attracted an increasing concern. In this study, Co-processing of CCS was developed via employing sintering and ironmaking combined technology for its harmless disposal and resource utilization. Crystalline phase and valence state transformation of chromium (Cr), technical feasibility assessment, leaching risk, characteristics of sintered products, and pollutant release during CCS co-processing were investigated through a series of laboratory-scale sintering pot experiments and large scale industrial trials. The results showed that the content of Cr(VI) in sintered products first increased then decreased with increasing temperature ranges of 300 °C-800 °C, and reached a maximum of 2189.64 mg/kg at 500 °C. 99.99% of Cr(VI) can be reduced to Cr(III) at above 1000 °C, which was attributed to the transformation of the Cr(VI)-containing crystalline phases (such as, MgCrO4 and CaCrO4) to the (Mg, Fe2+)(Cr, Al, Fe3+)2O4. The industrial trial results showed that adding 0.5 wt‰ CCS to sintering feed did not have adverse effects on the properties of the sintered ore and the plant's operating stability. The tumbler index of sinter was above 78% and the leaching concentrations of TCr (0.069 mg/L) was significantly lower than the Chinese National Standard of 1.0 mg/L (GB5085.3-2007). The TCr contents of sintering dust and blast furnace gas (BFG) scrubbing water were less than 0.19 wt‰ and 0.11 mg/L, respectively, which was far below the regulatory limit (1.5 mg/L, GB13456-2012). The mass balance evaluation results indicated that at least 89.9% of the Cr in the CCS migrated into the molten iron in the blast furnace (BF), which became a useful supplement to the molten iron. This study provided a new perspective strategy for the safe disposal and resource utilization of CCS in iron and steel industry.


Assuntos
Cromo , Esgotos , Cromo/química , Esgotos/química , Ferro/química
4.
Waste Manag ; 182: 207-214, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38670004

RESUMO

The objective of this paper is to evaluate the feasibility of co-processing wind turbine blade (WTB) material in cement manufacturing to provide an end-of-life means to divert the solid waste of decommissioned WTBs from landfills. Many WTBs consist primarily of glass fiber reinforced thermoset polymers that are difficult to recover or recycle. Portland cement is produced world-wide in large quantities, requiring immense quantities of raw materials (mostly calcium oxide and silicon oxide) and kiln temperatures approaching 1,450 °C. This work contributes analyses of WTB material composition, and predicts the energy provided through the combustible components of the WTBs and raw material contributions provided by incorporating the incombustible components of the WTBs to produce cement. Approximately 40 to 50 % of the WTB material will contribute as fuel to cement production, and approximately 50 to 60 % of the WTB material is expected to be incombustible. One tonne of WTB material can displace approximately 0.4 to 0.5 tonne of coal, while also contributing approximately 0.1 tonne of calcium oxide and 0.3 tonne of silicon oxide as raw material to the cement production process. The glass fiber WTB tested had an average boron content of 4.5 % in the ash. The effects of this high boron content on the cement and its production process should be evaluated. Co-processing WTBs in cement plants will slightly reduce combustion-related CO2 emissions due to avoided calcination. It seems feasible to co-process glass-fiber reinforced WTBs in cement production as WTBs provide suitable raw materials and compatible fuel for this process.


Assuntos
Materiais de Construção , Materiais de Construção/análise , Reciclagem/métodos , Vento , Compostos de Cálcio/química , Gerenciamento de Resíduos/métodos , Resíduos Sólidos/análise , Vidro , Óxidos
5.
AAPS PharmSciTech ; 25(4): 67, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519767

RESUMO

Despite being discovered over five decades ago, little is still known about ivermectin. Ivermectin has several physico-chemical properties that can result in it having poor bioavailability. In this study, polymorphic and co-crystal screening was used to see if such solid-state modifications can improve the oil solubility of ivermectin. Span® 60, a lipophilic non-ionic surfactant, was chosen as co-former. The rationale behind attempting to improve oil solubility was to use ivermectin in future topical and transdermal preparations to treat a range of skin conditions like scabies and head lice. Physical mixtures were also prepared in the same molar ratios as the co-crystal candidates, to serve as controls. Solid-state characterization was performed using X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The FTIR spectra of the co-crystal candidates showed the presence of Span® 60's alkyl chain peaks, which were absent in the spectra of the physical mixtures. Due to the absence of single-crystal X-ray data, co-crystal formation could not be confirmed, and therefore these co-crystal candidates were referred to as co-processed crystalline solids. Following characterization, the solid-state forms, physical mixtures and ivermectin raw material were dissolved in natural penetration enhancers, i.e., avocado oil (AVO) and evening primrose oil (EPO). The co-processed solids showed increased oil solubility by up to 169% compared to ivermectin raw material. The results suggest that co-processing of ivermectin with Span® 60 can be used to increase its oil solubility and can be useful in the development of oil-based drug formulations.


Assuntos
Ivermectina , Óleos , Solubilidade , Difração de Raios X , Composição de Medicamentos , Varredura Diferencial de Calorimetria , Espectroscopia de Infravermelho com Transformada de Fourier/métodos
6.
J Environ Manage ; 354: 120464, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38401504

RESUMO

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.


Assuntos
Cloro , Metais Pesados , Cádmio , Resíduos Perigosos/análise , Metais Pesados/análise
7.
Waste Manag Res ; 42(3): 260-272, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37382414

RESUMO

With global municipal solid waste generation increasing steadily, the importance of high-quality, environmentally friendly waste valorization methods is rising, too. Most countries have set themselves ambitious recycling goals and follow a waste hierarchy in which recycling is more preferable than energy recovery. This article focuses on a waste treatment option that already is an integral part of waste management in some countries and enables the simultaneous recovery of energy and mineral constituents: the production of solid recovered fuels (SRFs) from mixed municipal and commercial waste and their use in the cement industry is often referred to as co-processing. The state of the art of SRF production is described and the first comprehensive dataset for SRF samples including major constituents, heavy metal and metalloid contents, energy- and CO2-emission-relevant parameters, ash constituents and the material-recyclable share of SRF is presented. Additionally, a comparison with fossil fuels is given. It is concluded that SRF from state-of-the-art production plants complies with strict limit values for heavy metals, has an average biogenic carbon content of 60%, and its application in the cement industry can be considered as partial recycling (14.5%) and partial energy recovery (85.5%). Leaving no residues to be dealt with, co-processing of waste in the cement industry therefore offers many benefits and can support the shift from a linear to a circular economy.


Assuntos
Carbono , Gerenciamento de Resíduos , Indústrias , Reciclagem , Resíduos Sólidos
8.
Environ Monit Assess ; 195(11): 1380, 2023 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-37889377

RESUMO

Attention given to environmental pollution caused by environmental analytical (EA) laboratories is very poor in Sri Lanka (an economically developing country). This article discusses EA laboratory effluents and hazardous solid wastes, current environmental management practices, and the legislative requirements in Sri Lanka. Effluent quantities generated are low (29.99-63.09 L/week), but characterized with variable pH, high chemical oxygen demand (COD), total suspended solids (TSS) and heavy metals, and very high ecotoxicity. Quantities of chemical-contaminated solid wastes is 80-100 kg/year (excluding outdated and rejected chemicals). Most laboratories dispose chemical-contaminated solid wastes mixed with non-hazardous recyclables using the services of local authorities and some laboratories (particularly in areas where there is no municipal solid waste collection), practice backyard dumping or open burning, while a few laboratories employ private parties to dispose or burn these wastes elsewhere. Only one laboratory is disposing chemical-contaminated solid wastes through co-processing. Appropriate waste management strategies (including some cleaner production concepts) are discussed in this paper for selected streams of hazardous wastes.


Assuntos
Resíduos Perigosos , Eliminação de Resíduos , Laboratórios , Resíduos Sólidos , Países em Desenvolvimento , Sri Lanka , Monitoramento Ambiental , Análise da Demanda Biológica de Oxigênio
9.
Sci Total Environ ; 904: 166976, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37704153

RESUMO

Cement kiln co-processing is becoming the main strategy to dispose of hazardous waste containing Cr. A newly-discovered pentavalent Cr compound, which was proved to be formed during cement kiln co-processing of solid waste, is partly responsible for the water-soluble Cr released from the cement. However, the formation characteristics and the solubility of Cr(V) are still unclear to date. In this study, the reaction kinetics and further redox reactions of Cr(V) at high temperature were examined, and its crystal structure and solubility were also explored. At the temperature range of 1000-1200 °C, the formation rate of Ca5(CrO4)3O0.5 reached over 90 % within 10 min, and then slowly increased to near 100 % from 10 min to 10 h. shows that Ca5(CrO4)3O0.5 is formed by interface reaction at an early period, and by diffusion at a later period. The kinetic analysis indicates that Ca5(CrO4)3O0.5 is initially formed through an interface reaction and subsequently through diffusion. Ca5(CrO4)3O0.5 was identified and assigned as hexagonal crystal group (P63/m). Approximately 0.55 g and 0.15 g of Ca5(CrO4)3O0.5 dissolve in neutral water at 100 °C and 50 °C, and the concentrations of Cr(V) in water reach 550 and 150 mg/L, respectively. Additionally, this study finds that at the temperature range of 400-700 °C Ca5(CrO4)3O0.5 can be oxidized into CaCrO4, and at the temperature higher than 1400 °C, it can be further converted into Ca3(CrO4)2 and reduced into CaCr2O4. This study gives a deep insight into Cr oxidation-reduction reaction during thermal treatment of solid waste. These insights provide a comprehensive understanding of Cr oxidation-reduction reactions during the thermal treatment of solid waste, offering valuable guidance for waste management strategies.

10.
Materials (Basel) ; 16(13)2023 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-37444877

RESUMO

Due to its resistance to natural degradation and decomposition, plastic debris perseveres in the environment for centuries. As a lucrative material for packing industries and consumer products, plastics have become one of the major components of municipal solid waste today. The recycling of plastics is becoming difficult due to a lack of resource recovery facilities and a lack of efficient technologies to separate plastics from mixed solid waste streams. This has made oceans the hotspot for the dispersion and accumulation of plastic residues beyond landfills. This article reviews the sources, geographical occurrence, characteristics and recyclability of different types of plastic waste. This article presents a comprehensive summary of promising thermochemical technologies, such as pyrolysis, liquefaction and gasification, for the conversion of single-use plastic wastes to clean fuels. The operating principles, drivers and barriers for plastic-to-fuel technologies via pyrolysis (non-catalytic, catalytic, microwave and plasma), as well as liquefaction and gasification, are thoroughly discussed. Thermochemical co-processing of plastics with other organic waste biomass to produce high-quality fuel and energy products is also elaborated upon. Through this state-of-the-art review, it is suggested that, by investing in the research and development of thermochemical recycling technologies, one of the most pragmatic issues today, i.e., plastics waste management, can be sustainably addressed with a greater worldwide impact.

11.
Eur J Pharm Sci ; 188: 106528, 2023 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-37459903

RESUMO

In this study, insights into the development and optimization of a co-processed excipient based on mesoporous silica are presented. The main advantage of such a material is that it is appropriate for direct tablet compression and has a sufficiently large specific surface area to be suitable for potential subsequent drug loading and formulation of (amorphous) solid dispersions. Our aim was to use a Design of Experiments approach to investigate which process parameters in high shear granulation affect the characteristics of such a co-processed material. The parameters included were the amount of binder (isomalt), the amount of water (granulation liquid), the water addition rate and the speed of the impeller. The responses evaluated and modelled were particle size and its distribution, specific surface area, bulk density, flowability, compressibility and compactibility. The models obtained showed good quality in terms of goodness of fit and predictive power. Active effects were identified for all responses, giving a thorough insight into factors affecting the material characteristics. Optimization experiments resulted in products with the desired characteristics (high specific surface area, large particle size, good flow and compression properties) and confirmed the validity of the generated models.

12.
Chemosphere ; 336: 139187, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37336443

RESUMO

To decrease the environmental risks caused by heavy metals (HMs) in red mud (RM) and improve the quality of pyrolysis oil from biomass, high-temperature pretreated RM and cow dung (CD) were microwave co-pyrolyzed. Then, the optimization potential of energy consumption was evaluated and the interaction mechanism between RM and CD was explored. The results showed that the increase in transition metal oxides and specific surface area improved the microwave-absorption and catalytic capacity of the pretreated RM. By optimizing the parameters, a pretreatment temperature of 650 °C resulted in a 21.65% reduction in acid content of bio-oil, higher HMs immobilization rates (>91%) and a 7.44% reduction in energy consumption. The synergistic optimization of bio-oil quality, HMs immobilization and energy consumption was achieved. After microwave co-pyrolysis with cow dung, the larger specific surface area (92.90 m2 g-1) and higher carbon crystallinity (ID/IG = 1.02) of pyrolysis residues enhanced the physical adsorption to HMs. The complexation of HMs with -OH could further enhance the solidification of HMs. This work will provide support to efficient resource utilization of solid waste, and demonstrate the great potential of microwave co-pyrolysis in HMs immobilization.


Assuntos
Metais Pesados , Pirólise , Bovinos , Animais , Micro-Ondas , Polifenóis , Metais Pesados/química
13.
Carbohydr Polym ; 311: 120731, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37028868

RESUMO

Hydroxypropyl methylcellulose (HPMC) is an important polymeric excipient. Its versatility in terms of molecular weights and viscosity grades is the basis for its wide and successful application in the pharmaceutical industry. Low viscosity grades of HPMC (like E3 and E5) have been used as physical modifiers for pharmaceutical powders in recent years due to their unique physicochemical and biological properties (e.g., low surface tension, high Tg, strong hydrogen bonding ability, etc.). Such modification is the co-processing of HPMC with a drug/excipient to create composite particles (CPs) for the purpose of providing synergistic effects of functional improvement as well as of masking undesirable properties of the powder (e.g., flowability, compressibility, compactibility, solubility, stability, etc.). Therefore, given its irreplaceability and tremendous opportunities for future developments, this review summarized and updated studies on improving the functional properties of drugs and/or excipients by forming CPs with low-viscosity HPMC, analyzed and exploited the improvement mechanisms (e.g., improved surface properties, increased polarity, hydrogen bonding, etc.) for the further development of novel co-processed pharmaceutical powders containing HPMC. It also provides an outlook on the future applications of HPMC, aiming to provide a reference on the crucial role of HPMC in various areas for interested readers.


Assuntos
Excipientes , Metilcelulose , Pós , Derivados da Hipromelose/química , Viscosidade , Excipientes/química , Propriedades de Superfície , Metilcelulose/química , Solubilidade
14.
Front Chem ; 11: 1165402, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37082230

RESUMO

Using municipal and industrial solid waste as a substitute raw material and fuel in cement rotary kiln co-processing is considered an economic and environmentally friendly alternative to the use of traditional fuels. However, the presence of heavy metals in solid waste is a growing concern in the cement rotary kiln co-processing technique. The solidification mechanism of heavy metals in cement clinker is directly related to their stabilization. Cement clinkers doped with manganese oxide (MnO2: 0.0%-5.0% wt%) were prepared in a laboratory to investigate the impacts of extrinsic Mn on cement clinker calcination. The insignificant changes in X-ray diffractometer patterns indicated that the fixed Mn had little influence on the mineral lattice structure. Raman spectra and X-ray photoelectron spectroscopy revealed the transformation of the silicate phase when the Mn dose was increased. Moreover, the satisfactory solidification ratio confirmed the incorporation of Mn in the cement clinker. These results provided evidence of the influence rule of Mn in the cement clinker calcination process. Furthermore, Raman spectroscopy showed great potential for the qualitative and semi-quantitative analysis of the cementitious materials derived from cement rotary kiln co-processing. These results will be important for the further development of green cement manufacturing technology.

15.
Bioresour Technol ; 380: 129061, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37075852

RESUMO

To achieve the main goal of net zero carbon emission, the shift from conventional fossil-based energy/products to renewable and low carbon-based energy/products is necessary. Biomass has been perceived as a carbon-neutral source from which energy and value-added products can be derived, while sludge is a slurry waste that inherently contains high amount of minerals and organic matters. Hence, thermochemical co-processing of biomass wastes and sludge could create positive synergistic effects, resulting in enhanced performance of the process (higher conversion or yield) and improved qualities or characteristics of the products as compared to that of mono-processing. This review presents the current progress and development for various thermochemical techniques of biomass-sludge co-conversion to energy and high-value products, and the potential applications of these products from circular economy's point of view. Also, these technologies are discussed from economic and environmental standpoints, and the outlook towards technology maturation and successful commercialization is laid out.


Assuntos
Energia Renovável , Esgotos , Biomassa , Fenômenos Físicos , Carbono
16.
J Pharm Sci ; 112(8): 2010-2028, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-36780986

RESUMO

Active Pharmaceutical Ingredients (APIs) do not always exhibit processable physical properties, which makes their processing in an industrial setup very demanding. These issues often lead to poor robustness and higher cost of the drug product. The issue can be mitigated by co-processing the APIs using suitable solvent media-based techniques to streamline pharmaceutical manufacturing operations. Some of the co-processing methods are the amalgamation of API purification and granulation steps. These techniques also exhibit adequate robustness for successful adoption by the pharmaceutical industry to manufacture high quality drug products. Spherical crystallization and co-precipitation are solvent media-based co-processing approaches that enhances the micromeritic and dissolution characteristics of problematic APIs. These methods not only improve API characteristics but also enable direct compression into tablets. These methods are economical and time-saving as they have the potential for effectively circumventing the granulation step, which can be a major source of variability in the product. This review highlights the recent advancements pertaining to these techniques to aid researchers in adopting the right co-processing method. Similarly, the possibility of scaling up the production of co-processed APIs by these techniques is discussed. The continuous manufacturability by co-processing is outlined with a short note on Process Analytical Technology (PAT) applicability in monitoring and improving the process.


Assuntos
Indústria Farmacêutica , Tecnologia Farmacêutica , Cristalização/métodos , Tecnologia Farmacêutica/métodos , Indústria Farmacêutica/métodos , Comprimidos/química , Solventes/química , Preparações Farmacêuticas
17.
J Pharm Sci ; 112(8): 2069-2078, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36638959

RESUMO

These proceedings contain presentation summaries and discussion highlights from the University of Maryland Center of Excellence in Regulatory Science and Innovation (M-CERSI) Workshop on Co-processed API, held on July 13 and 14, 2022. This workshop examined recent advances in the use of co-processed active pharmaceutical ingredients as a technology to improve drug substance physicochemical properties and drug product manufacturing process robustness, and explored proposals for enabling commercialization of these transformative technologies. Regulatory considerations were discussed with a focus on the classification, CMC strategies, and CMC documentation supporting the use of this class of materials from clinical studies through commercialization. The workshop format was split between presentations from industry, academia and the FDA, followed by breakout sessions structured to facilitate discussion. Given co-processed API is a relatively new concept, the authors felt it prudent to compile these proceedings to gain further visibility to topics discussed and perspectives raised during the workshop, particularly during breakout discussions. Disclaimer: This paper reflects discussions that occurred among stakeholder groups, including FDA, on various topics. The topics covered in the paper, including recommendations, therefore, are intended to capture key discussion points. The paper should not be interpreted to reflect alignment on the different topics by the participants, and the recommendations provided should not be used in lieu of FDA published guidance or direct conversations with the Agency about a specific development program. This paper should not be construed to represent FDA's views or policies.

18.
J Hazard Mater ; 446: 130680, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36592557

RESUMO

Development of co-processing technology in the cement industry in China is important for environmentally sound disposal and recycling of waste, and contributes to sustainable development of the cement industry. However, dioxin pollution could negatively affect promotion of this technology. Therefore, it is necessary to study the emission characteristics of dioxins in cement kilns. In this study, the emission characteristics of dioxins and factors influencing their generation during co-processing solid wastes were studied in 14 new dry cement kilns. The dioxin concentrations were very similar regardless of whether solid wastes were fed into the kiln. In blank runs without co-processing, the average dioxin concentration was 0.0097 ng international toxic equivalents (I-TEQ)/Nm3. By comparison, that for co-processing solid wastes was 0.012 ng I-TEQ/Nm3. These values meet the relevant emission standards. The type of co-processed solid wastes had almost no effect on the dioxin concentration. At larger production scales, the concentration of dioxin emitted in the flue gas decreased. The dioxin concentrations in kiln dust were obviously higher than those in clinker and raw materials. The average emission factor of dioxin per ton of cement was 30 ng I-TEQ/t, which is equivalent to that in cement kilns in other countries.

19.
Environ Sci Pollut Res Int ; 30(10): 24804-24814, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34837105

RESUMO

This paper deals with the techniques to use plastic waste for co-processing in cement kiln for energy recovery. Plastics, a versatile material and friend to the common man, have now become one of the most serious environmental issues when it is discarded into the environment. The focus of this study is on eco-friendly disposal of plastic waste. Plastic is user-friendly, but because of its incomplete lifecycle, it has become a global issue. It is commonly disposed of by land filling or incinerating the waste, which adds to the pollution load at later stages. The authors' focus is on innovative techniques to use waste plastics in different proportions for the co-processing in cement kiln in order to highlight the energy recovery of the entire plant. It is a good solution to the waste disposal problems that arise due to plastic waste as well as municipal solid waste. The use of plastic waste as an alternative fuel for cement plants is suggested in this paper. The authors also promote this approach and suggest encouraging its calorific value utilization in the cement manufacturing plant. A systematic approach has been presented in this work to mitigate the energy consumption in the cement industries as well as environmental hazards due to plastic and municipal solid waste.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Humanos , Resíduos Sólidos/análise , Plásticos , Eliminação de Resíduos/métodos , Reciclagem/métodos
20.
J Pharm Sci ; 112(8): 2046-2056, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36462708

RESUMO

Continuous direct compression (CDC) of solid oral dosage forms requires materials exhibiting acceptable flow and compression properties. The desired active pharmaceutical ingredient (API) powder properties can be difficult to achieve through conventional particle engineering approaches, such as particle size and habit modification during crystallization. Co-processing of API with excipients can significantly improve the powder properties to overcome these difficulties. In this manuscript, performance of a co-processed API was evaluated in a continuous feeding and blending process using GEA ConsiGma® Continuous Dosing and Blending Unit (CDB1). The co-processed theophylline was generated via a methodology in which polymer was precipitated and coated the crystalline theophylline particles resulting in nearly spherical agglomerates. A range of drug loads (1-25% w/w), flow rates (15-40 kg/h) and blender speeds (220-400 rpm) were studied. The results demonstrated that the co-processed API can be successfully fed through a loss-in-weight feeder and blended with other excipients in a high shear blender to generate tablets with acceptable content uniformity at 1-25% w/w drug loads. This study supports that using co-processed API with enhanced powder properties is a promising approach to enable continuous manufacturing for APIs with challenging properties.


Assuntos
Química Farmacêutica , Farmácia , Química Farmacêutica/métodos , Excipientes/química , Pós/química , Teofilina , Comprimidos/química , Tamanho da Partícula , Composição de Medicamentos/métodos , Tecnologia Farmacêutica/métodos
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