I. Aroun, Nabila Bensacia, N. Taoualit, Lylia Djadi, Amina Iakhlef
The study focuses on the synthesis of two adsorbent forms that were prepared: magnetic nonporous hybrid beads (MNPHB), and magnetic macroporous hybrid beads (MMPHB). The salicylic acid adsorption tests on MNPHB and MMPHB were carried out at a temperature of 25 °C, pH 4, adsorbent mass of 10 mg, and an initial concentration of 10 mg l −1 . The adsorption capac ity was found to be for MNPHP and MMPHB to 9 mg g −1 and 152 mg g −1 , respectively. The adsorption kinetic was described by the pseudo-second order model and Freundlich isotherm for the MMPHB beads.
{"title":"Synthesis and Characterisation of Novel Magnetic Beads as Salicylic Acid Adsorbents from an Aqueous Solution","authors":"I. Aroun, Nabila Bensacia, N. Taoualit, Lylia Djadi, Amina Iakhlef","doi":"10.15255/kui.2021.036","DOIUrl":"https://doi.org/10.15255/kui.2021.036","url":null,"abstract":"The study focuses on the synthesis of two adsorbent forms that were prepared: magnetic nonporous hybrid beads (MNPHB), and magnetic macroporous hybrid beads (MMPHB). The salicylic acid adsorption tests on MNPHB and MMPHB were carried out at a temperature of 25 °C, pH 4, adsorbent mass of 10 mg, and an initial concentration of 10 mg l −1 . The adsorption capac ity was found to be for MNPHP and MMPHB to 9 mg g −1 and 152 mg g −1 , respectively. The adsorption kinetic was described by the pseudo-second order model and Freundlich isotherm for the MMPHB beads.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42661262","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}
Carbon and silicon are similar chemical elements, being the members of the same, 14 th (4B), group of the periodic system; not only in science fiction but also in serious scientific works could there be found speculations about the possibility of extra-terrestrial life based on silicon. In this paper, the physical and chemical properties of carbon and silicon, as well as their respective compounds were compared (alkanes – silanes, cyclic hydrocarbons – cyclosilicates, heterocyclic compounds – alumosilicates). Their geochemistry shows mutual dependence of carbon and sil - icon circulations. Moreover, comparison of silica (quartz) with water (ice) points to unexpected similarities of the two minerals.
{"title":"Ugljik, silicij, kisik: kemijska analogija živog i neživog","authors":"N. Raos","doi":"10.15255/kui.2020.058","DOIUrl":"https://doi.org/10.15255/kui.2020.058","url":null,"abstract":"Carbon and silicon are similar chemical elements, being the members of the same, 14 th (4B), group of the periodic system; not only in science fiction but also in serious scientific works could there be found speculations about the possibility of extra-terrestrial life based on silicon. In this paper, the physical and chemical properties of carbon and silicon, as well as their respective compounds were compared (alkanes – silanes, cyclic hydrocarbons – cyclosilicates, heterocyclic compounds – alumosilicates). Their geochemistry shows mutual dependence of carbon and sil - icon circulations. Moreover, comparison of silica (quartz) with water (ice) points to unexpected similarities of the two minerals.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42124641","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 purpose of this study was to assess the antioxidant activity of the fresh extracts of Croatian and Greek watermelon seeds. Samples were prepared using two extraction methods: Soxhlet and maceration. Ethanol was used as a solvent in the Soxhlet, and methanol in the maceration method. The mass fractions of the extracts obtained by maceration were lower compared to those obtained by the Soxhlet method. The antioxidant capacity of fresh watermelon-seed extracts was determined by DPPH (2,2-diphenyl-1-picrylhydrazyl radical) method. The antioxidant capacity of the extracts was also expressed via IC 50 (half maximal inhibitory concentration). Based on the obtained IC 50 values (1.41 to 2.60 mg ml −1 ), all tested extracts showed antiradical activity but antioxidant capacity was better in extracts obtained by the maceration method. The reason for this may be the use of methanol as a solvent, which was to be expected, since methanol is a more polar solvent than ethanol. The neutralisation capacity of DPPH radicals of analysed extracts was compared to the neutralisation capacity of ascorbic acid as standard. The concentrations of tested extracts required to neutralize 50 % of DPPH radicals were significantly higher than the required concentration of ascorbic acid (0.25 mg ml −1 ).
{"title":"Antioxidant Activity of Watermelon Seeds Determined by DPPH Assay","authors":"M. Salihović, M. Pazalja, A. Ajanović","doi":"10.15255/kui.2021.064","DOIUrl":"https://doi.org/10.15255/kui.2021.064","url":null,"abstract":"The purpose of this study was to assess the antioxidant activity of the fresh extracts of Croatian and Greek watermelon seeds. Samples were prepared using two extraction methods: Soxhlet and maceration. Ethanol was used as a solvent in the Soxhlet, and methanol in the maceration method. The mass fractions of the extracts obtained by maceration were lower compared to those obtained by the Soxhlet method. The antioxidant capacity of fresh watermelon-seed extracts was determined by DPPH (2,2-diphenyl-1-picrylhydrazyl radical) method. The antioxidant capacity of the extracts was also expressed via IC 50 (half maximal inhibitory concentration). Based on the obtained IC 50 values (1.41 to 2.60 mg ml −1 ), all tested extracts showed antiradical activity but antioxidant capacity was better in extracts obtained by the maceration method. The reason for this may be the use of methanol as a solvent, which was to be expected, since methanol is a more polar solvent than ethanol. The neutralisation capacity of DPPH radicals of analysed extracts was compared to the neutralisation capacity of ascorbic acid as standard. The concentrations of tested extracts required to neutralize 50 % of DPPH radicals were significantly higher than the required concentration of ascorbic acid (0.25 mg ml −1 ).","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43576534","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}
V. Beluli, Mehdi Berisha, Ismet Mulliqi, Kathellina Kristollari, L. Salihu
Gjilan is a city located in southeast Kosovo. The main supplier of drinking water for the city is the Përlepnica Lake where heavy metals in sediment and water, and physicochemical parameters were analysed. Average concentrations of metals in soil sediment were found in the following order: Mn (708.65 mg kg −1 ) > Zn (604.55 mg kg −1 ) > Pb (264.26 mg kg −1 ) > Cr (71.43 mg kg −1 ) > Cu (61.08 mg kg −1 ) > Ni (37.27 mg kg −1 ) > Cd (6.32 mg kg −1 ) > Fe (1.83 mg kg −1 ). Average concentrations of metals in water were found in the following order: Fe (0.295 mg l −1 ) > Zn (0.066 mg l −1 ) > Cu (0.020 mg l −1 ) > Cr (0.035 mg l −1 ) > Cd (0.003 mg l −1 ) > Mn (0.003 mg l −1 ). The concentrations of heavy metals in sediment, such as Cd, Cu, Mn, Pb, and Zn, were not in accordance with the “New Dutch List” (soil and ground water criteria used in The Netherlands for contaminated land), and the concentration of Fe and Cu in water was not in accordance with EU Directive 75/440.
吉兰是位于科索沃东南部的一个城市。城市饮用水的主要来源是Përlepnica湖，对沉积物和水中的重金属进行了理化参数分析。土壤沉积物中金属的平均浓度顺序为:Mn (708.65 mg kg−1)> Zn (604.55 mg kg−1)> Pb (264.26 mg kg−1)> Cr (71.43 mg kg−1)> Cu (61.08 mg kg−1)> Ni (37.27 mg kg−1)> Cd (6.32 mg kg−1)> Fe (1.83 mg kg−1)。水中金属的平均浓度顺序为:Fe (0.295 mg l - 1) > Zn (0.066 mg l - 1) > Cu (0.020 mg l - 1) > Cr (0.035 mg l - 1) > Cd (0.003 mg 1) > Mn (0.003 mg 1 - 1)。沉积物中Cd、Cu、Mn、Pb、Zn等重金属的浓度不符合“新荷兰清单”(荷兰对受污染土地使用的土壤和地下水标准)，水中Fe和Cu的浓度不符合欧盟指令75/440。
{"title":"Concentration of Heavy Metals in Sediment and Water of Përlepnica Lake, Kosovo","authors":"V. Beluli, Mehdi Berisha, Ismet Mulliqi, Kathellina Kristollari, L. Salihu","doi":"10.15255/kui.2021.060","DOIUrl":"https://doi.org/10.15255/kui.2021.060","url":null,"abstract":"Gjilan is a city located in southeast Kosovo. The main supplier of drinking water for the city is the Përlepnica Lake where heavy metals in sediment and water, and physicochemical parameters were analysed. Average concentrations of metals in soil sediment were found in the following order: Mn (708.65 mg kg −1 ) > Zn (604.55 mg kg −1 ) > Pb (264.26 mg kg −1 ) > Cr (71.43 mg kg −1 ) > Cu (61.08 mg kg −1 ) > Ni (37.27 mg kg −1 ) > Cd (6.32 mg kg −1 ) > Fe (1.83 mg kg −1 ). Average concentrations of metals in water were found in the following order: Fe (0.295 mg l −1 ) > Zn (0.066 mg l −1 ) > Cu (0.020 mg l −1 ) > Cr (0.035 mg l −1 ) > Cd (0.003 mg l −1 ) > Mn (0.003 mg l −1 ). The concentrations of heavy metals in sediment, such as Cd, Cu, Mn, Pb, and Zn, were not in accordance with the “New Dutch List” (soil and ground water criteria used in The Netherlands for contaminated land), and the concentration of Fe and Cu in water was not in accordance with EU Directive 75/440.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43524149","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}
Larbi Mahmoudi, A. Djafer, Samia Benhammadi, H. Aguedal, A. Iddou, D. Achour
Hexavalent chromium is one of the hazardous metals that can be found in industrial effluents such as wood treatment units, mining, leather tanning, pigment, steel and electroplating industry . The present work aimed to evaluate the self-purification capacity of the microbial flora taken from the domestic wastewater effluent of Chlef City, with the perspective of designing a microbial bed in the secondary sewage treatment to prevent an industrial Cr(VI) contamination. Under various operating conditions, the bioremoval performance of Cr(VI) was evaluated by using suspended biomass and immobilised biomass (fixed onto pozzolana grains). The results showed that the immobilised biomass was more efficient and more resistant to Cr(VI) toxicity than the suspended biomass. Indeed, the Cr(VI) was totally eliminated within 96 h for an initial concentration of 50 mg l −1 by the immobilised biomass, while this rate was obtained after 120 h for the suspended biomass. The kinetic data fit well to the pseudo-first order kinetic model. The intraparticle diffusion kinetic model suggested that the diffusion process of Cr(VI) was greatly influenced by the initial concentration. The microbial flora present in domestic wastewater is a promising biosorbent that is able to treat effluent containing Cr(VI).
{"title":"Bioremoval Performances of Hexavalent Chromium by Suspended and Immobilised Microbial Biomass onto Pozzolana: Studying the Self-purification Mechanism","authors":"Larbi Mahmoudi, A. Djafer, Samia Benhammadi, H. Aguedal, A. Iddou, D. Achour","doi":"10.15255/kui.2021.054","DOIUrl":"https://doi.org/10.15255/kui.2021.054","url":null,"abstract":"Hexavalent chromium is one of the hazardous metals that can be found in industrial effluents such as wood treatment units, mining, leather tanning, pigment, steel and electroplating industry . The present work aimed to evaluate the self-purification capacity of the microbial flora taken from the domestic wastewater effluent of Chlef City, with the perspective of designing a microbial bed in the secondary sewage treatment to prevent an industrial Cr(VI) contamination. Under various operating conditions, the bioremoval performance of Cr(VI) was evaluated by using suspended biomass and immobilised biomass (fixed onto pozzolana grains). The results showed that the immobilised biomass was more efficient and more resistant to Cr(VI) toxicity than the suspended biomass. Indeed, the Cr(VI) was totally eliminated within 96 h for an initial concentration of 50 mg l −1 by the immobilised biomass, while this rate was obtained after 120 h for the suspended biomass. The kinetic data fit well to the pseudo-first order kinetic model. The intraparticle diffusion kinetic model suggested that the diffusion process of Cr(VI) was greatly influenced by the initial concentration. The microbial flora present in domestic wastewater is a promising biosorbent that is able to treat effluent containing Cr(VI).","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48388487","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}
Phosphorus, provided by phosphorus fertilisers, is one of the essential nutrients for the healthy growth of plants. Phosphate rocks are strategic resources for phosphorus in agriculture and their supply will become very limited in the near future. As a raw material, phosphorus availability shows a decreasing trend over the last decades upon excessive consumption of phosphate rocks. Moreover, excessive application of conventional phosphorus fertilisers is the primary driving force for eutrophication. Utilisation of engineered nanomaterials in agriculture provides precise delivery of nutrients, together with decreasing the neg- ative environmental impacts of excessive usage of mineral fertilisers. Studies on enhancing the phosphorus uptake efficiency have priority in order to maintain agricultural productivity. Hydroxyapatite nanoparticles can be an innovative approach as a new group of phosphorus fertilisers, offering promising potential for enhancement of agronomic yield and reduction of eutrophication. This study provides a brief review of novel approaches for developing more strategic and efficient routes for phosphorus uptake upon hydroxyapatite utilisation in order to improve crop production.
{"title":"A Novel Assessment Strategy for Nanotechnology in Agriculture: Evaluation of Nanohydroxyapatite as an Alternative Phosphorus Fertiliser","authors":"Cemre Avşar","doi":"10.15255/kui.2021.057","DOIUrl":"https://doi.org/10.15255/kui.2021.057","url":null,"abstract":"Phosphorus, provided by phosphorus fertilisers, is one of the essential nutrients for the healthy growth of plants. Phosphate rocks are strategic resources for phosphorus in agriculture and their supply will become very limited in the near future. As a raw material, phosphorus availability shows a decreasing trend over the last decades upon excessive consumption of phosphate rocks. Moreover, excessive application of conventional phosphorus fertilisers is the primary driving force for eutrophication. Utilisation of engineered nanomaterials in agriculture provides precise delivery of nutrients, together with decreasing the neg- ative environmental impacts of excessive usage of mineral fertilisers. Studies on enhancing the phosphorus uptake efficiency have priority in order to maintain agricultural productivity. Hydroxyapatite nanoparticles can be an innovative approach as a new group of phosphorus fertilisers, offering promising potential for enhancement of agronomic yield and reduction of eutrophication. This study provides a brief review of novel approaches for developing more strategic and efficient routes for phosphorus uptake upon hydroxyapatite utilisation in order to improve crop production.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47575850","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}
Malaysia’s palm oil industry generates a huge amount of palm kernel shell (PKS) waste. Utilising PKS as a sand replacement in brick production is one of the viable solutions to reduce biomass waste. The water absorption test revealed that the char-PKS absorbs significantly more water than the PKS-brick. The compression strength indicated that PKS masonry bricks meet Ma - laysian standards and American Society for Testing and Materials. According to the density test, the bricks with the maximum sand replacement fall into the lightweight range. This research has sparked hope of reducing PKS waste by using it as a partial replacement for sand in brick production.
{"title":"Fibreglass Reinforcement Integrated with Palm Kernel Shell as Partial Replacement of Sand for Brick Production","authors":"M. S. M. Zaini, Mohamad Adam Bin Mohd Za'aim","doi":"10.15255/kui.2021.067","DOIUrl":"https://doi.org/10.15255/kui.2021.067","url":null,"abstract":"Malaysia’s palm oil industry generates a huge amount of palm kernel shell (PKS) waste. Utilising PKS as a sand replacement in brick production is one of the viable solutions to reduce biomass waste. The water absorption test revealed that the char-PKS absorbs significantly more water than the PKS-brick. The compression strength indicated that PKS masonry bricks meet Ma - laysian standards and American Society for Testing and Materials. According to the density test, the bricks with the maximum sand replacement fall into the lightweight range. This research has sparked hope of reducing PKS waste by using it as a partial replacement for sand in brick production.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41825391","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}
Uporaba mikroorganizama u obliku biofilma sve je češći način biološke obrade jer reaktori s biofilmom na nosačima daju zadovoljavajuće rezultate obrade otpadnih voda različitog podrijetla te se intenzivno istražuju i unaprjeđuju. Dizajn uređaja za obradu otpadnih voda, unaprjeđenje postojećih reaktora i njihove učinkovitosti te rješavanje problematičnih točaka pri obradi otpadnih voda olakšano je matematičkim modeliranjem pomoću dostupnih modela, ovisno o njegovoj svrsi. Modeliranje u praksi zahtijeva promišljanje i prilagodbu modelu i njegovim pretpostavkama te postaje nezamjenjiv dio modernih istraživanja i izgradnje sustava za obradu otpadne vode. ABSTRACT Increasingly stringent regulatory requirements, greater wastewater generation, and limited space necessitate new wastewater treatment processes. Biofilm-based treatment technologies have prov en to be efficient and applicable. The results of wastewater treatment using biofilm reactors with different types of carriers and the associated community of microorganisms support their use for wastewater treatment of different origins and degradation products present. Biofilm formation begins with the adsorption of molecules on the surface to form a film that can have several effects, such as altering surface properties and suppressing or enhancing the release of toxic metal ions from the surface. Subsequently, the microorganisms begin to coalesce into a microcolony and then into a three-dimensional biofilm structure. The biofilm cells detach from the structure and form a new biofilm. Common to is the sludge easy handling, higher of protection of microorganisms from environmental changes and allowing the growth of slow-growing microorganisms, which are important for the degradation of complex compounds. Although modelling of biofilm reactors is not uniform, there are instructions for the most accurate modelling, so the results obtained are useful and reduce the time for modelling as well as for design/improvement of the plant and thus saving resources. The number of models available is increasing, and the choice depends on their purpose and the expertise of the operator.
Uporaba mikrorganizima u obliku biomat sve ječešći način biološke obrade jer reaktori s biomat na nosačima daju zadovoljavajuće rezultate obrade otpadnih voda različitog podrijetla te se intentizivno istražuju i unaprje uju。Dizajn ure-j aja za obradu otpadnih voda，unparje dj enje postojećih reaktora i njihove učinkovitosti te rješavanje problematičnih točaka pri obradi otpadnih-voda olakšano je matematičkim modeliranjem pomoću dostupnih modela，ovisno o njegovoj svrsi。praksi zahtijeva promišljanje的模型是一个新的模型，它是一个现代化的模型。摘要越来越严格的监管要求、更大的废水产生量和有限的空间都需要新的废水处理工艺。基于生物膜的处理技术已被证明是有效和适用的。使用具有不同类型载体和相关微生物群落的生物膜反应器处理废水的结果支持它们用于处理不同来源和存在的降解产物的废水。生物膜的形成始于分子在表面上的吸附，形成一层具有多种作用的膜，如改变表面性质、抑制或增强有毒金属离子从表面的释放。随后，微生物开始聚结为微菌落，然后形成三维生物膜结构。生物膜细胞与结构分离并形成新的生物膜。常见的是污泥易于处理，对微生物免受环境变化的保护更高，并允许缓慢生长的微生物生长，这对复杂化合物的降解很重要。尽管生物膜反应器的建模并不统一，但有最准确建模的说明，因此所获得的结果是有用的，可以减少建模以及工厂设计/改进的时间，从而节省资源。可用型号的数量正在增加，选择取决于其用途和操作员的专业知识。
{"title":"Primjena i modeliranje sustava s biofilmom u obradi otpadnih voda","authors":"Tea Štefanac, Dijana Grgas, Blaženko Marjanović, Tibela Landeka Dragičević","doi":"10.15255/kui.2021.050","DOIUrl":"https://doi.org/10.15255/kui.2021.050","url":null,"abstract":"Uporaba mikroorganizama u obliku biofilma sve je češći način biološke obrade jer reaktori s biofilmom na nosačima daju zadovoljavajuće rezultate obrade otpadnih voda različitog podrijetla te se intenzivno istražuju i unaprjeđuju. Dizajn uređaja za obradu otpadnih voda, unaprjeđenje postojećih reaktora i njihove učinkovitosti te rješavanje problematičnih točaka pri obradi otpadnih voda olakšano je matematičkim modeliranjem pomoću dostupnih modela, ovisno o njegovoj svrsi. Modeliranje u praksi zahtijeva promišljanje i prilagodbu modelu i njegovim pretpostavkama te postaje nezamjenjiv dio modernih istraživanja i izgradnje sustava za obradu otpadne vode. ABSTRACT Increasingly stringent regulatory requirements, greater wastewater generation, and limited space necessitate new wastewater treatment processes. Biofilm-based treatment technologies have prov en to be efficient and applicable. The results of wastewater treatment using biofilm reactors with different types of carriers and the associated community of microorganisms support their use for wastewater treatment of different origins and degradation products present. Biofilm formation begins with the adsorption of molecules on the surface to form a film that can have several effects, such as altering surface properties and suppressing or enhancing the release of toxic metal ions from the surface. Subsequently, the microorganisms begin to coalesce into a microcolony and then into a three-dimensional biofilm structure. The biofilm cells detach from the structure and form a new biofilm. Common to is the sludge easy handling, higher of protection of microorganisms from environmental changes and allowing the growth of slow-growing microorganisms, which are important for the degradation of complex compounds. Although modelling of biofilm reactors is not uniform, there are instructions for the most accurate modelling, so the results obtained are useful and reduce the time for modelling as well as for design/improvement of the plant and thus saving resources. The number of models available is increasing, and the choice depends on their purpose and the expertise of the operator.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48211220","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 aim of current work was to carry out a fine characterisation of the structural, physicochemical, and thermal properties of octenyl succinic anhydride (OSA)-modified waxy maize starch known under the marketed name Gel ‘N’ MeltTM. Both Fourier transform infrared spectroscopy and proton nuclear magnetic resonance analyses revealed the presence of new absorption bands and confirmed the structure of OSA-modified starch in comparison with those of native starch. The results of proton nuclear magnetic resonance analysis were consistent with those obtained using the titration method. The molecular weight obtained was regarded as higher than those found for other starch modified sources; an inverse correlation between the degree of substitution and the molecular weight was deduced: a decrease in the degree of substitution was followed by an increase in the molecular weight. In addition, X-ray diffraction and scanning electron microscopy revealed the loss of the ordered A-type crystalline structure, which is characteristic of polymers with low degree of substitution. Also, a coexistence of individual and aggregate particles was observed, supported by the extent of the fusion of grains. These results were corroborated by thermal analysis experiments, which showed a total loss of the crystallinity of the heated grains.
{"title":"Structural, Physicochemical and Thermal Properties of OSA-modified Waxy Maize Starch","authors":"Amel Djori, N. Moulai-Mostefa","doi":"10.15255/kui.2021.005","DOIUrl":"https://doi.org/10.15255/kui.2021.005","url":null,"abstract":"The aim of current work was to carry out a fine characterisation of the structural, physicochemical, and thermal properties of octenyl succinic anhydride (OSA)-modified waxy maize starch known under the marketed name Gel ‘N’ MeltTM. Both Fourier transform infrared spectroscopy and proton nuclear magnetic resonance analyses revealed the presence of new absorption bands and confirmed the structure of OSA-modified starch in comparison with those of native starch. The results of proton nuclear magnetic resonance analysis were consistent with those obtained using the titration method. The molecular weight obtained was regarded as higher than those found for other starch modified sources; an inverse correlation between the degree of substitution and the molecular weight was deduced: a decrease in the degree of substitution was followed by an increase in the molecular weight. In addition, X-ray diffraction and scanning electron microscopy revealed the loss of the ordered A-type crystalline structure, which is characteristic of polymers with low degree of substitution. Also, a coexistence of individual and aggregate particles was observed, supported by the extent of the fusion of grains. These results were corroborated by thermal analysis experiments, which showed a total loss of the crystallinity of the heated grains.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47412654","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}
Ahmed Chabane, F. Bouchal, Mohamed Hentabli, F. Rezgui, Houssam Eddine Slama
This work aimed to model the kinetics of cumulative drug release from formulations based on encapsulation by biodegradable polycaprolactone and polyvinylpyrrolidone polymers. Different ratios of the polymerswere prepared by a solvent evaporation method using Span 20 and Span 80 as surfactants. The cumulative drug release was estimated depending on the formulation component and time. Four models: hybrid model of support vector machine and dragonfly algorithm (DA-SVM), partial least squares (PLS) model, multiple linear regression (MLR) model, and ordinary least squared (OLS) model, were developed and compared. The statistical analysis proved there were no issues in variable inputs. The results showed that the DA-SVM model gave a better result where a determination coefficient was close to one and RMSE error close to zero. A graphical interface was built to calculate the cumulative drug release.
{"title":"Cumulative Drug Release Modelling of PCL-PVP Encapsulated Tramadol by DA-SVM, MLR, PLS, and OLS Regression Techniques","authors":"Ahmed Chabane, F. Bouchal, Mohamed Hentabli, F. Rezgui, Houssam Eddine Slama","doi":"10.15255/kui.2021.008","DOIUrl":"https://doi.org/10.15255/kui.2021.008","url":null,"abstract":"This work aimed to model the kinetics of cumulative drug release from formulations based on encapsulation by biodegradable polycaprolactone and polyvinylpyrrolidone polymers. Different ratios of the polymerswere prepared by a solvent evaporation method using Span 20 and Span 80 as surfactants. The cumulative drug release was estimated depending on the formulation component and time. Four models: hybrid model of support vector machine and dragonfly algorithm (DA-SVM), partial least squares (PLS) model, multiple linear regression (MLR) model, and ordinary least squared (OLS) model, were developed and compared. The statistical analysis proved there were no issues in variable inputs. The results showed that the DA-SVM model gave a better result where a determination coefficient was close to one and RMSE error close to zero. A graphical interface was built to calculate the cumulative drug release.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49585708","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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