Manorma Sharma, A. Simões, Patrícia Alves, Licínio M. Gando- Ferreira
Black liquor (BL) from kraft pulping industries contains a large fraction of lignin and hemicelluloses and their efficient separation can open up new possibilities for integrated biorefineries. In this work, lignin and hemicelluloses were separated from BL and concentrated BL (obtained by ultrafiltration), by precipitation using acidification and antisolvent precipitation method, respectively. For lignin precipitation, different organic acids, namely acetic, lactic and citric acid, were used and the yield and purity of the extracted lignin were compared with the lignin precipitated using inorganic acids, namely sulphuric and phosphoric acid. Among the organic acids, the highest yield of lignin (57.2%) was obtained by lactic acid, but the extract also contained the highest levels of inorganic impurities (9.2%). The extract obtained from acetic acid contained lower inorganic impurities and the lignin yield was 48.1%. The hemicellulose was extracted from BL liquor that was concentrated using the ZnObased PES mixed matrix ultrafiltration membrane, which was started by first separating lignin (at pH 3.5, 4 and 4.5) from it. The supernatants from the lignin precipitation process were used as a source of hemicellulose and this was precipitated by using acetone as an antisolvent. The highest hemicellulose yield (54.4%) was obtained from the supernatant with the lowest lignin content and highest acetone to supernatant ratio. Keywords: acidification, antisolvent precipitation, hemicelluloses, kraft black liquor, lignin
{"title":"Efficient Recovery of Lignin and Hemicelluloses from Kraft Black Liquor","authors":"Manorma Sharma, A. Simões, Patrícia Alves, Licínio M. Gando- Ferreira","doi":"10.18502/kms.v7i1.11602","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11602","url":null,"abstract":"Black liquor (BL) from kraft pulping industries contains a large fraction of lignin and hemicelluloses and their efficient separation can open up new possibilities for integrated biorefineries. In this work, lignin and hemicelluloses were separated from BL and concentrated BL (obtained by ultrafiltration), by precipitation using acidification and antisolvent precipitation method, respectively. For lignin precipitation, different organic acids, namely acetic, lactic and citric acid, were used and the yield and purity of the extracted lignin were compared with the lignin precipitated using inorganic acids, namely sulphuric and phosphoric acid. Among the organic acids, the highest yield of lignin (57.2%) was obtained by lactic acid, but the extract also contained the highest levels of inorganic impurities (9.2%). The extract obtained from acetic acid contained lower inorganic impurities and the lignin yield was 48.1%. The hemicellulose was extracted from BL liquor that was concentrated using the ZnObased PES mixed matrix ultrafiltration membrane, which was started by first separating lignin (at pH 3.5, 4 and 4.5) from it. The supernatants from the lignin precipitation process were used as a source of hemicellulose and this was precipitated by using acetone as an antisolvent. The highest hemicellulose yield (54.4%) was obtained from the supernatant with the lowest lignin content and highest acetone to supernatant ratio. \u0000Keywords: acidification, antisolvent precipitation, hemicelluloses, kraft black liquor, lignin","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"179 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77487689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pre-hydrolysis-kraft of Eucalyptus globulus by autohydrolysis (batch) and with dilute acid hydrolysis (flow-through reactor) were explored in this study, to examine the recovery of xylooligosaccharides (XOs) from the pre-hydrolysis treatment. The results of this work support the potential reuse of the hydrolysate to increase the recovery yield of added value compounds. The pH of the dilute acid hydrolysis was maintained at 3.5 with acetic acid, to mimic the conditions of the batch reactor medium (autohydrolysis). An increase of XOs recovered was evident when the pre-treatment was in the flow-through reactor instead of the batch reactor. In the latter, a high concentration of furfural was recovered, showing the influence of time in XO conversion through hydrolysis. The total yield of pulp was higher in the flow-through reactor (36.4%) in comparison with the batch system (34.5%) after kraft pulping, which was expected, given the increasing time that the hydrolysate was present in the reactor; however, the difference was small and could have been the result of precipitated compounds in the latter, so this needs further analysis. Keywords: cellulose, Eucalyptus globulus, pre-hydrolysis kraft, xylooligosaccharides
{"title":"Effect of Pre-Hydrolysis Reaction Conditions on Xylooligosaccharides Extraction in Eucalyptus Globulus","authors":"A. Cunha, R. Simões","doi":"10.18502/kms.v7i1.11603","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11603","url":null,"abstract":"Pre-hydrolysis-kraft of Eucalyptus globulus by autohydrolysis (batch) and with dilute acid hydrolysis (flow-through reactor) were explored in this study, to examine the recovery of xylooligosaccharides (XOs) from the pre-hydrolysis treatment. The results of this work support the potential reuse of the hydrolysate to increase the recovery yield of added value compounds. The pH of the dilute acid hydrolysis was maintained at 3.5 with acetic acid, to mimic the conditions of the batch reactor medium (autohydrolysis). An increase of XOs recovered was evident when the pre-treatment was in the flow-through reactor instead of the batch reactor. In the latter, a high concentration of furfural was recovered, showing the influence of time in XO conversion through hydrolysis. The total yield of pulp was higher in the flow-through reactor (36.4%) in comparison with the batch system (34.5%) after kraft pulping, which was expected, given the increasing time that the hydrolysate was present in the reactor; however, the difference was small and could have been the result of precipitated compounds in the latter, so this needs further analysis. \u0000Keywords: cellulose, Eucalyptus globulus, pre-hydrolysis kraft, xylooligosaccharides","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81105436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The increasing demands for water for multiple purposes combined with climate change challenges are leading to water scarcity and quality deterioration. Portugal is vulnerable to the impacts of climate change and therefore, the use of reclaimed waters has been identified as a suitable alternative water source for non-potable uses, such as irrigation, to overcome water shortages. In the last two years, new policies for water reuse have been approved at the Portuguese and European levels. The legal frameworks are supported in the international guidelines developed by the International Organization for Standardization, namely for irrigation, urban uses and health risk assessment. In this way, all reuse projects must follow a fit-for-purpose approach, i.e., the water quality needs to meet the requirements of its specific end-uses without compromising public health or the surrounding environment, and all reuse projects must conduct a risk assessment for health and the environment. Quantitative, qualitative or semiquantitative models can be used. Although a quantitative assessment may be desirable, these models tend to be complex and present high uncertainty. Furthermore, these usually require extensive data which are often not available. Accordingly, this study intended to develop a conceptual model to deal with the risk assessment for water resources, namely surface and ground waters. A semi-quantitative approach was employed for the risk characterization, using empirical qualitative judgment to assess the relative importance of hazards, exposure routes, scenarios and barriers in place. The use of a strategic assessment allows the quality standards that meet the needs of each project to be validated. The developed model was applied to a case study to illustrate its applicability. Keywords: water reuse, water resources, risk assessment, semi-quantitative model, compounds of emerging concern
{"title":"Water Reuse: A Risk Assessment Model for Water Resources","authors":"A. Rebelo, Albertina Bento Amaro, F. Quadrado","doi":"10.18502/kms.v7i1.11623","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11623","url":null,"abstract":"The increasing demands for water for multiple purposes combined with climate change challenges are leading to water scarcity and quality deterioration. Portugal is vulnerable to the impacts of climate change and therefore, the use of reclaimed waters has been identified as a suitable alternative water source for non-potable uses, such as irrigation, to overcome water shortages. In the last two years, new policies for water reuse have been approved at the Portuguese and European levels. The legal frameworks are supported in the international guidelines developed by the International Organization for Standardization, namely for irrigation, urban uses and health risk assessment. In this way, all reuse projects must follow a fit-for-purpose approach, i.e., the water quality needs to meet the requirements of its specific end-uses without compromising public health or the surrounding environment, and all reuse projects must conduct a risk assessment for health and the environment. Quantitative, qualitative or semiquantitative models can be used. Although a quantitative assessment may be desirable, these models tend to be complex and present high uncertainty. Furthermore, these usually require extensive data which are often not available. Accordingly, this study intended to develop a conceptual model to deal with the risk assessment for water resources, namely surface and ground waters. A semi-quantitative approach was employed for the risk characterization, using empirical qualitative judgment to assess the relative importance of hazards, exposure routes, scenarios and barriers in place. The use of a strategic assessment allows the quality standards that meet the needs of each project to be validated. The developed model was applied to a case study to illustrate its applicability. \u0000Keywords: water reuse, water resources, risk assessment, semi-quantitative model, compounds of emerging concern","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73387963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Marchiori, André Studart, Maria Vitoria Morais, A. Albuquerque, L. A. Andrade Pais, Maria Eugênia Boscov, V. Cavaleiro
Biomass ashes (BA) have been intensively studied as amendments for soil in earthworks. This paper aimed to geotechnically characterize BA from pines and olive trees compared to the soil from Castelo Branco, Portugal. Namely, granulometry, specific gravity, Atterberg limits and optimal compaction values were obtained and analyzed in order to valorize the residue incorporated into soils. This work is part of broader efforts to develop an alternative material that can be used in hydraulic barriers as liners and for soil reinforcement. Thus, BA can contribute to reductions in weight and plasticity, and filling properties. Further studies are needed, particularly mechanical and hydraulic performance tests. Keywords: biomass ashes, geotechnical and mechanical properties, residue valorization, soil reinforcement, liner material
{"title":"Geotechnical Characterization of Biomass Ashes for Soil Reinforcement and Liner Material","authors":"L. Marchiori, André Studart, Maria Vitoria Morais, A. Albuquerque, L. A. Andrade Pais, Maria Eugênia Boscov, V. Cavaleiro","doi":"10.18502/kms.v7i1.11626","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11626","url":null,"abstract":"Biomass ashes (BA) have been intensively studied as amendments for soil in earthworks. This paper aimed to geotechnically characterize BA from pines and olive trees compared to the soil from Castelo Branco, Portugal. Namely, granulometry, specific gravity, Atterberg limits and optimal compaction values were obtained and analyzed in order to valorize the residue incorporated into soils. This work is part of broader efforts to develop an alternative material that can be used in hydraulic barriers as liners and for soil reinforcement. Thus, BA can contribute to reductions in weight and plasticity, and filling properties. Further studies are needed, particularly mechanical and hydraulic performance tests. \u0000Keywords: biomass ashes, geotechnical and mechanical properties, residue valorization, soil reinforcement, liner material","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90813571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Baptista, Luís Santos, Maria Emília Amaral, Lucia Maria Silva
Essential oils (EOs) are acclaimed for their antimicrobial properties, leading to their multiple applications in various fields. In this work, four aromatic plants were used, namely thyme (Thymus mastichina L.), everlasting (Helychrysum stoechas Moench), European pennyroyal (Mentha pulegium L.) and fennel (Foeniculum vulgare Mill.). Hydrodistillation was the extraction method used, and the obtained extracts were composed of a variety of volatile molecules, mainly terpenoids and phenylpropenoids. The EO yields were determined, and the chemical composition of these natural products was obtained by gas chromatography-mass spectrometry (GC-MS) analysis. The yields varied greatly in the range of 0.99 to 4.27% (v/w). The two major chemical constituents of the EOs analysed by GC-MS were as follows: thyme – 1,8-cineole and champhor; everlasting – α-pinene and limonene; European pennyroyal – pulegone and isomenthone; fennel – trans-anethole and limonene. This preliminary study is an important contribution to the understanding of EO bioactive compounds that are under investigation to establish their ability to control the biocolonization of cultural heritage. Keywords: aromatic plants, chemical characterization, essential oils, green biocides
{"title":"Chemical Characterization of Essential Oils With a Biocide Base for Conservation and Restoration","authors":"C. Baptista, Luís Santos, Maria Emília Amaral, Lucia Maria Silva","doi":"10.18502/kms.v7i1.11611","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11611","url":null,"abstract":"Essential oils (EOs) are acclaimed for their antimicrobial properties, leading to their multiple applications in various fields. In this work, four aromatic plants were used, namely thyme (Thymus mastichina L.), everlasting (Helychrysum stoechas Moench), European pennyroyal (Mentha pulegium L.) and fennel (Foeniculum vulgare Mill.). Hydrodistillation was the extraction method used, and the obtained extracts were composed of a variety of volatile molecules, mainly terpenoids and phenylpropenoids. The EO yields were determined, and the chemical composition of these natural products was obtained by gas chromatography-mass spectrometry (GC-MS) analysis. The yields varied greatly in the range of 0.99 to 4.27% (v/w). The two major chemical constituents of the EOs analysed by GC-MS were as follows: thyme – 1,8-cineole and champhor; everlasting – α-pinene and limonene; European pennyroyal – pulegone and isomenthone; fennel – trans-anethole and limonene. This preliminary study is an important contribution to the understanding of EO bioactive compounds that are under investigation to establish their ability to control the biocolonization of cultural heritage. \u0000Keywords: aromatic plants, chemical characterization, essential oils, green biocides","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89616328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Silva, Ana Maria Antão-Geraldes, P. Scalize, V. Cavaleiro, A. Albuquerque
The removal of residual pollutants from a synthetic effluent with a composition similar to that of urban effluent from secondary treatment was evaluated in vertical downflow columns. These were filled with soil, the fine fraction of the soil, and sand, and operated in discontinuous and continuous mode. The results showed high removal rates of organic matter, ammonium, nitrate and phosphate in the discontinuous and continuous experiments, especially for the fine fraction. Therefore, the soil is suitable for removing organic matter and nutrients (N-NH4, N-NO3, and P-PO4), and can be used for polishing wastewater before its infiltration. Keywords: wastewater reuse, organics removal, nutrient removal, residual soil, river sand
{"title":"Influence of Hydraulic Conditions on Reclaimed Water Polishing Using Soil and Sand Columns","authors":"F. Silva, Ana Maria Antão-Geraldes, P. Scalize, V. Cavaleiro, A. Albuquerque","doi":"10.18502/kms.v7i1.11617","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11617","url":null,"abstract":"The removal of residual pollutants from a synthetic effluent with a composition similar to that of urban effluent from secondary treatment was evaluated in vertical downflow columns. These were filled with soil, the fine fraction of the soil, and sand, and operated in discontinuous and continuous mode. The results showed high removal rates of organic matter, ammonium, nitrate and phosphate in the discontinuous and continuous experiments, especially for the fine fraction. Therefore, the soil is suitable for removing organic matter and nutrients (N-NH4, N-NO3, and P-PO4), and can be used for polishing wastewater before its infiltration. \u0000Keywords: wastewater reuse, organics removal, nutrient removal, residual soil, river sand","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73560633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pigments from natural sources, such as bacterial pigments, have gained increased attention in recent years due to their biodegradability, non-toxicity, and noncarcinogenicity. The intention to replace synthetic and oil-derived compounds is not restricted to synthetic dyes; other applications include the replacement of oilderived polymers for more environmentally friendly options, such as biopolymers. In this work, the functionalization of a bacterial cellulose (BC) biopolymer with bacterial pigments was explored using a full factorial design methodology to evaluate the best functionalization conditions to produce colored BC. From the factors and interactions evaluated, it was possible to conclude that the variable duration of the functionalization procedure could be reduced to a low level without significantly affecting the functionalization of the BC samples with bacterial pigments. Moreover, BC is a product with high industrial applicability, versatility, and sustainability. Hence, the multifunctional colored BC can be applied in the packaging, paper, and textile industries, among others. Keywords: bacterial pigments, bacterial cellulose, full-factorial design, optimization
{"title":"Functionalization of Bacterial Cellulose With Bacterial Pigments: Optimization Using a Full Factorial Design Approach","authors":"Lúcia F. A. Amorim, R. Fangueiro, I. Gouveia","doi":"10.18502/kms.v7i1.11608","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11608","url":null,"abstract":"Pigments from natural sources, such as bacterial pigments, have gained increased attention in recent years due to their biodegradability, non-toxicity, and noncarcinogenicity. The intention to replace synthetic and oil-derived compounds is not restricted to synthetic dyes; other applications include the replacement of oilderived polymers for more environmentally friendly options, such as biopolymers. In this work, the functionalization of a bacterial cellulose (BC) biopolymer with bacterial pigments was explored using a full factorial design methodology to evaluate the best functionalization conditions to produce colored BC. From the factors and interactions evaluated, it was possible to conclude that the variable duration of the functionalization procedure could be reduced to a low level without significantly affecting the functionalization of the BC samples with bacterial pigments. Moreover, BC is a product with high industrial applicability, versatility, and sustainability. Hence, the multifunctional colored BC can be applied in the packaging, paper, and textile industries, among others. \u0000Keywords: bacterial pigments, bacterial cellulose, full-factorial design, optimization","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75481625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The “Entre-os-Rios” thermal aquifer has a protection perimeter buffer zone for avoiding water contamination. A vulnerability map was generated, using geographic information systems (GIS) tools and the DRASTIC index, to evaluate the risk of contamination of the perimeter area. The results showed that the protection perimeter buffer zone has an insignificant to moderate risk of pollution, with the DRASTIC index’s values ranging from 47 to 127 points, and an average pollution vulnerability of 79 points. The alluvium-covered land is vulnerable to moderate contamination but is located far from the catchment point. Areas of minimal risk correspond to locations where the granitic massif has not been altered significantly. Keywords: geographic information systems, vulnerability map, protection perimeter buffer zone, DRASTIC index
{"title":"Evaluation of Entre-os-Rios Thermal Aquifer Vulnerability Using DRASTIC Index","authors":"Vanessa Gonçalves, A. Albuquerque, V. Cavaleiro","doi":"10.18502/kms.v7i1.11628","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11628","url":null,"abstract":"The “Entre-os-Rios” thermal aquifer has a protection perimeter buffer zone for avoiding water contamination. A vulnerability map was generated, using geographic information systems (GIS) tools and the DRASTIC index, to evaluate the risk of contamination of the perimeter area. The results showed that the protection perimeter buffer zone has an insignificant to moderate risk of pollution, with the DRASTIC index’s values ranging from 47 to 127 points, and an average pollution vulnerability of 79 points. The alluvium-covered land is vulnerable to moderate contamination but is located far from the catchment point. Areas of minimal risk correspond to locations where the granitic massif has not been altered significantly. \u0000Keywords: geographic information systems, vulnerability map, protection perimeter buffer zone, DRASTIC index","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77857718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Boaventura Borges, A. Baia, A. Lopes, M. Pacheco, L. Ciríaco, A. Fernandes
Electro-Fenton process was applied in the degradation of the textile dye C. I. Direct Red 80 (DR80), using a boron-doped diamond anode and a carbon-felt cathode. The influence of the applied current density and of the type of iron source was evaluated. The iron sources studied were iron sulfate, ferric chloride, iron oxide and chalcopyrite, a natural iron-containing mineral. The obtained results showed that the electro-Fenton process is effective in the DR80 degradation and in the pollutant load elimination. Higher treatment efficiencies were attained when using iron sulfate as iron source. Still, the results obtained with the natural mineral chalcopyrite were quite promising. Although DR80 removal was more efficient at lower applied current densities, the same was not observed for the chemical oxygen demand removal, indicating that, at lower applied current densities, the dye is not completely mineralized, but rather transformed into other by-products. Keywords: C. I. Direct Red 80; Advanced oxidation processes; Electro-Fenton, Borondoped diamond anode, Carbon-felt cathode.
{"title":"Degradation of C. I. Direct Red 80 by the Electro-Fenton Process","authors":"Boaventura Borges, A. Baia, A. Lopes, M. Pacheco, L. Ciríaco, A. Fernandes","doi":"10.18502/kms.v7i1.11612","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11612","url":null,"abstract":"Electro-Fenton process was applied in the degradation of the textile dye C. I. Direct Red 80 (DR80), using a boron-doped diamond anode and a carbon-felt cathode. The influence of the applied current density and of the type of iron source was evaluated. The iron sources studied were iron sulfate, ferric chloride, iron oxide and chalcopyrite, a natural iron-containing mineral. The obtained results showed that the electro-Fenton process is effective in the DR80 degradation and in the pollutant load elimination. Higher treatment efficiencies were attained when using iron sulfate as iron source. Still, the results obtained with the natural mineral chalcopyrite were quite promising. Although DR80 removal was more efficient at lower applied current densities, the same was not observed for the chemical oxygen demand removal, indicating that, at lower applied current densities, the dye is not completely mineralized, but rather transformed into other by-products. \u0000Keywords: C. I. Direct Red 80; Advanced oxidation processes; Electro-Fenton, Borondoped diamond anode, Carbon-felt cathode.","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"92 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73621245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Madeira, F. Carvalho, M. Ribau Teixeira, A. Almeida
In this study, slaughterhouse wastewater previously treated by immediate one-step lime precipitation was treated using a vertical flow constructed wetland (VFCW). A VFCW pilot scale planted with Vetiveria zizanioides in light expanded clay aggregates was used to study the influence of the organic load applied (3 to 212 g m−2 d−1) and the bed depth of the VFCW (0.35 and 0.70 m) on the organic matter removal (COD). Two VFCWs operated in parallel under continuous flow, and a hydraulic load of around 80 L m−2 d−1 was used. The results indicated that an increase in the organic load decreased COD removal efficiency. The bed depth of the VFCW had a significant influence on the removal of organic matter, with greater removal at high bed depths. For organic loads applied up to 9.5 g m−2 d−1, COD removal efficiencies of 71.4 ± 4.0% and 85.2 ± 3.4% were observed for lower and higher VFCW bed depth, respectively, which met the requirements for water reuse for irrigation. Throughout the tests, Vetiveria zizanioides did not show signs of toxicity, and its growth was substantial. Keywords: slaughterhouse wastewater, vertical flow constructed wetlands, Vetiveria zizanioides, organic matter removal, immediate one-step lime precipitation
在本研究中，采用垂直流人工湿地(VFCW)处理屠宰场废水。利用VFCW中试规模，研究了施加的有机负荷(3 ~ 212 g m−2 d−1)和VFCW的层深(0.35和0.70 m)对有机物质去除率(COD)的影响。两个VFCWs在连续流量下并联运行，水力负荷约为80 L m−2 d−1。结果表明，随着有机负荷的增加，COD去除率降低。VFCW的床层深度对有机物的去除率有显著影响，高床层深度对有机物的去除率较大。当施加有机负荷为9.5 g m−2 d−1时，较低和较高VFCW床深的COD去除率分别为71.4±4.0%和85.2±3.4%，满足灌溉用水回用的要求。在整个试验过程中，香根草没有显示出毒性迹象，而且它的生长是可观的。关键词:屠宰场废水，垂直流人工湿地，香根草，有机物去除，立即一步石灰沉淀
{"title":"Phytoremediation as a Sustainable Alternative for Organic Matter Removal From Slaughterhouse Wastewater Pretreated by Immediate One-Step Lime Precipitation","authors":"L. Madeira, F. Carvalho, M. Ribau Teixeira, A. Almeida","doi":"10.18502/kms.v7i1.11621","DOIUrl":"https://doi.org/10.18502/kms.v7i1.11621","url":null,"abstract":"In this study, slaughterhouse wastewater previously treated by immediate one-step lime precipitation was treated using a vertical flow constructed wetland (VFCW). A VFCW pilot scale planted with Vetiveria zizanioides in light expanded clay aggregates was used to study the influence of the organic load applied (3 to 212 g m−2 d−1) and the bed depth of the VFCW (0.35 and 0.70 m) on the organic matter removal (COD). Two VFCWs operated in parallel under continuous flow, and a hydraulic load of around 80 L m−2 d−1 was used. The results indicated that an increase in the organic load decreased COD removal efficiency. The bed depth of the VFCW had a significant influence on the removal of organic matter, with greater removal at high bed depths. For organic loads applied up to 9.5 g m−2 d−1, COD removal efficiencies of 71.4 ± 4.0% and 85.2 ± 3.4% were observed for lower and higher VFCW bed depth, respectively, which met the requirements for water reuse for irrigation. Throughout the tests, Vetiveria zizanioides did not show signs of toxicity, and its growth was substantial. \u0000Keywords: slaughterhouse wastewater, vertical flow constructed wetlands, Vetiveria zizanioides, organic matter removal, immediate one-step lime precipitation","PeriodicalId":17908,"journal":{"name":"KnE Materials Science","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82270892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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