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- CO2 Capture in Chemically and Thermally Modified Activated Carbons Using Breakthrough Measurements: Experimental and Modeling StudyPublication . Silva, José A.C.; Karimi, Mohsen; Gonçalves, Carmem Natália de Pina; Díaz de Tuesta, Jose Luis; Rodrigues, Alírio; Gomes, HelderThe development of adsorption-based technologies for CO2 capture in the post combustion processes requires finding materials with high capacity of adsorption and low cost of preparation. In this study, the modification of a commercial activated carbon (Norit ROX 0.8), considered as a solid adsorbent for CO2 capture, and the effects of different methods of activations, chemically (hydrogen peroxide, sulfuric acid, nitric acid, and urea) and thermally (at 800 °C) on adsorption performance, have been investigated. Then, CO2 adsorption capacity was studied at different temperatures and pressures to evaluate the effects of various agents on sample performance. The textural properties of the samples were determined using adsorption−desorption isotherms of nitrogen at −196 °C. Finally, the obtained data were modeled by Response Surface Methodology (RSM) and Langmuir isotherm. The results showed that the prepared sample by successive treatments with nitric acid, urea, and thermal calcination has a higher uptake capacity than other modified samples.
- Uptake capacity of adsorbent materials derived from municipal solid waste for CO2 capture at post combustion conditionPublication . Díaz de Tuesta, Jose Luis; Karimi, Mohsen; Gonçalves, Carmem Natália de Pina; Silva, José A.C.; Gomes, Helder; Rodrigues, AlírioThe global climate change, as well as the accumulations of solid waste on landfills, are two of the primary issues nowadays, which it needs the significant attempts to reduce the impact on the ecosystem and environment from both of them [1]. In this work, the production of materials from organic solid waste is considered to produce adsorbent materials, which are assessed in the CO2 capture.
- Compost from municipal solid wastes as a source of biochar for CO2 capturePublication . Karimi, Mohsen; Díaz de Tuesta, Jose Luis; Gonçalves, Carmem Natália de Pina; Gomes, Helder; Rodrigues, Alírio; Silva, José A.C.ncreasing greenhouse gas emissions contributing to the global climate change are a major concern of environmental protection. Developing adsorbents from low-cost and renewable resources is an attractive strategy. On the other hand, the high capacity of production rates of municipal solid waste, besides high methane emissions, is the origin of some eco-systemic challenges. The combination of the two environmental problems is considered by introducing the compost from a mechanical biological treatment of municipal solid wastes as a low-cost source of adsorbent for CO2 capture. The obtained compost was thermally and chemically activated and the CO2 adsorption capacities of prepared samples were evaluated. Samples prepared sequentially with sulfuric acid and heated at 800 degrees C and vice versa, respectively, had the highest uptake capacities and were comparable with commercial adsorbents.
- Comparison between the ability of sulphuric acid, nitric acid and urea as chemical activators of commercial activated carbons for CO2 capturePublication . Gonçalves, Carmem Natália de Pina; Karimi, Mohsen; Díaz de Tuesta, Jose Luis; Silva, José A.C.; Rodrigues, Alírio; Gomes, HelderPhysical adsorption process has been considered as a promising technique for CO2 capture, due to low energy consumption and high efficiency. In this way, several adsorbents including activated carbons [1], zeolites [2] and MOFs [3] have been extensively studied for CO2 adsorption in the recent years. Activated carbon has attracted much attention, because of amorphous porous form, hydrophobic character and low energy for desorption [4]. To preparation of this adsorbent, physically (thermally) and chemically methods are the two main strategies. In the first method, the materials are carbonized in the temperature range of 400-850 0C, while in the second one by using some chemical components activation takes place by heating the mixture of precursor and dehydrating agent or oxidant. Hereby, based on BLUE Map Scenario of the International Energy Agency (IEA) [5], an activated carbon (Norit ROX 0.8) has been modified by using different chemical and thermal treatments, following the procedures described elsewhere [6]. In order to obtain adsorbents with smaller particle size, commercial activated carbon was first grinded and sieved to particle sizes ranging from 0.106 to 0.250 mm, resulting in a powder activated carbon (PAC). Three of the materials were prepared directly from the PAC sample by liquid phase treatments with hydrogen peroxide, sulphuric acid and nitric acid, resulting in PACHP, PACSA and PACNA materials, respectively. The treatment with hydrogen peroxide was performed wetting 25 g of PAC with 500 mL of hydrogen peroxide solution 30% (w/v) at room temperature for 24 h. In sulphuric acid oxidation, 25 g of PAC was immersed in 500 mL of 18 M acid solution for 3 h at 423 K. Oxidation with nitric acid was carried out boiling 25 g of PAC in 500 mL of 5 M nitric acid solution for 3 h. After the liquid phase treatments, all samples were thoroughly washed with distilled water until the neutrality of the rinsing waters and further dried in oven for 18 h at 383 K, resulting in samples PACHP, PACSA and PACNA, respectively. The other two samples were obtained in successive treatments of the PACNA material. 2 g of PACNA was immersed in 50 mL of 1 M urea solution and kept in a 125 mL stainless steel high pressure batch reactor under its own atmosphere at 473 K for 2 h, the recovered solids being thoroughly washed with distilled water until the neutrality of the rinsing waters, and further dried overnight in oven at 383 K, resulting in the PACNAU material. Then, a gas phase thermal treatment was applied, in which 1 g of PACNAU was heated, under a N2 flow (100 cm3 min−1), at 393 K, 673 K and 873 K during 60 min at each temperature and then at 1073 K for 240 min, resulting in the PACNAUT material.
- Breakthrough measurement of carbon dioxide adsorption on lowcost activated carbons derived from solid wastesPublication . Karimi, Mohsen; Díaz de Tuesta, Jose Luis; Gonçalves, Carmem Natália de Pina; Silva, José A.C.; Rodrigues, Alírio; Gomes, HelderIn this study, based on the scopes of CCS strategy and municipal solid waste management, a novel Integrated Environment Management (IEM) strategy has been proposed. In this way, the obtained compost in the mechanical biological treatment from municipal solid wastes has been considered as a source of adsorbents for CO2 capture. In this way, the maturated compost waste was modified by liquid phase treatment with sulfuric acid and thermal treatment at 800 0C. Then, the prevalent operational conditions of post-combustion processes have been considered to find the best prepared samples for CO2 capture.
- Enhancing single and multi-component adsorption efficiency of pharmaceutical emerging contaminants using bio waste-derived carbon materials and geopolymersPublication . Silva, Ana P. F.; Baldo, Arthur P.; Silva, Adriano S.; Natal, Ana Paula S.; Bezerra, Ana J.B.; Tuesta, Jose L. Diaz de; Marin, Pricila; Peres, José A.; Gomes, HelderWater contamination with pharmaceuticals like acetaminophen (ACT), sulfamethoxazole (SMX), and phenolic compounds such as gallic acid (GA), have become a global concern. These contaminants are persistent environmental pollutants that threaten aquatic life and human health. Adsorption is recognized as an efficient and low-cost solution to tackle water pollution. In this study, the efficiency of three adsorbents—activated carbon (AC), geopolymer (GP), and carbon nanotubes (CNT) prepared from solid wastes for the removal of ACT, SMX, and GA by adsorption is assessed. AC, GP and CNT are synthesized from real wastes to address solid waste management needs. Physisorption confirmed AC superior BET surface area (527 m2 g 1), followed by CNTs (66 m2 g 1) and GPs (30 m2 g 1), allowing to achieve the highest adsorption capacity: 126.8 mg g 1 for ACT, 54.9 mg g 1 for SMX, and 151.5 mg g 1 for GA, with respective breakthrough times of 314, 66, and 68 min. Kinetic and isotherm adsorption models are fitted for all pair pollutant-adsorbent reaching 33 equations to accurately predict adsorption process, concluding that pseudo-second-order kinetic and Freundlich model best fit experimental data, demonstrating a strong adsorbent-adsorbate affinity. The findings suggest that these sustainable materials offer promising solutions for treating contaminated water.
- Ultralight microcellular polyurethanes for the production of technical footwear componentsPublication . Rafael, Helder Martins; Fernandes, Isabel P.; Gomes, Helder; Pinto, Vera; Fernandes, A.M.; Ferreira, Maria José; Barreiro, M.F.Today's society demands lightweight and comfortable footwear products, which represents a market opportunity for the footwear industry, motivating the development of new low-density (ultralight) materials. This research is dedicated to the development of ultralight microcellular polyurethanes (PUs) with suitable properties for the production of midsoles for technical footwear. In this context, the studies performed in this work aimed at reduce the density of microcellular PUs by the incorporation of additives based on expandable thermoplastic microspheres. Samples of a base formulation were modified by the incorporation of 1, 2 and 3% of the additive. The produced materials result in PUs with densities that varied from 0.45 to 0.30 g/cm3. The performed characterization pointed out for PUs with adequate technical properties, with particular emphasis for impact absorption, which evidenced the suitability of the developed materials for the production of midsoles for ultralight safety shoes.
- [Ir(m-SC(CH3)3)(CO)2]2: um novo precursor de irídio para a produção de filmes por OMCVD sobre substratos de grafitePublication . Gomes, Helder; Faria, Joaquim; Figueiredo, José; Feurer, Roselyne; Kalck, Philippe; Serp, Philippe
- Preparation and characterization of natural and pillared clays for catalytic wet peroxide oxidation of 4-nitrophenolPublication . Díaz de Tuesta, Jose Luis; Kalmakhanova, Marzhan; Massalimova, Bakytgul Kabykenovna; Gomes, HelderThis work deals with the evaluation of two natural clays (NCs) extracted from Karatau (KNC) and Akzhar (ANC) deposits (located in the Zhambyl region of Kazakhstan) to prepare pillared clays (PILCs) for catalytic wet peroxide oxidation (CWPO) of 4-nitrophenol (4-NP), used as model pollutant. NCs were washed with HCl 1 M and then pillared using a solution containing Fe, Cu and Zr. NCs and PILCs were characterized by Electron Microprobe (EMP), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM), as detailed elsewhere [1,2]. EMP confirms the cation exchange of the Ca contained in the NCs (Ca > 15%) in the form of calcite (according to DRX and FTIR), by polycations of the pillaring solution (Ca < 2% for the PILCs). TEM reveals that the impregnation of polycations on the washed NCs also take place, coupling with its pillarization. CWPO runs were performed following the methodology and operational conditions described in previous works [1,2]. All materials show catalytic activity, since the H2O2 is consumed (Fig. 1A) to oxidize the 4-NP. Both KPILC and APILC, prepared from KNC and ANC, respectively, allow the complete removal of 4-NP after 4 h, whereas the conversion of 4-NP was less than 20% with the NCs (Fig. 1B). TOC conversions higher than 60 % were achieved with PILCs after 8 h. The subtraction of the theoretical TOC contribution of 4-NP from experimental TOC allowed to observe the formation of oxidazable intermediate compounds (maximum value of TOCexperimental- TOC4-NP at 1 h of reaction), which are oxidized to form refractory products (Fig. 1C). Based on these contributions of the TOC, a kinetic model based on TOC lumping into three blocks (TOCA à TOCB à TOCC, corresponding to the initial TOC of 4-NP, oxidazable intermediates and refractory products, respectively) was developed for the NCs and PILCs, predicting suitably the evolution of 4-NP, H2O2 and TOC in the CWPO of 4-NP (Fig. 1).
- Application of catalysts developed from compost derived from municipal solid waste in the removal of caffeine by wet peroxide oxidationPublication . Almeida, Flávio V.M.; Oliveira, Jéssica; Díaz de Tuesta, Jose Luis; Praça, Paulo; Guerreiro, Mário C.; Barreiro, M.F.; Silva, Adrián; Faria, Joaquim; Gomes, Helder; Oliveira, JessícaNowadays, waste management through mechanical biological treatment (MBT) consists on the use of the separated organic fraction of municipal solid waste (MSW) to feed anaerobic digestion processes, resulting therein a solid stream, further processed to compost, which can be used as fertilizer. Currently, the production of compost from MBT is higher than the existing demand, and the expected developments on up-coming directives ruling “End-of-waste” criteria are leading to barriers on the use of waste-derived fertilizers (European Commision, 2013). In this context, the current work proposes an alternative strategy to the valorisation of compost, through the production of low-cost materials to be applied in the catalytic wet peroxide oxidation (CWPO) of synthetic wastewater effluents contaminated with caffeine, used as a model pollutant of emerging concern. Caffeine is the most consumed psychoactive drug worldwide. It is one of the components of painkillers, medication against migraine, fatigue, drowsiness and breathing problems. Its consumption is also associated with an overall lower risk of malignant growth like hepatocellular, endometrial or colorectal cancer (Ganzenko et al., 2015). However, the effect of caffeine and its environmental degradation products on aquatic living species is not properly known. Caffeine, is a world wide consumed psychoactive drug, in a way that becomes a persistent compound and cannot be efficiently removed by municipal wastewater treatment facilities (Ganzenko et al., 2015). As a consequence, caffeine and its metabolites are present in the effluents of wastewater treatment plants (Gracia-Lor et al., 2017).