Kemija u Industriji-Journal of Chemists and Chemical Engineers最新文献

{"title":"Modelling and Multi-response Optimisation of Leachate Treatment by Electrocoagulation using Full Central Composite Design","authors":"Ridha Lessoued, Ahmet Azizi, M. Lati, T. Ahmed Zaid","doi":"10.15255/kui.2021.085","DOIUrl":"https://doi.org/10.15255/kui.2021.085","url":null,"abstract":"Electrocoagulation has lately received much interest as an effective method for the treatment of landfill leachate because of its ease of use, low cost, and environmental friendliness. The present study aimed to investigate the reduction of chemical organic demand (COD), biological organic demand (BOD 5 ), and turbidity from leachate by electrocoagulation process using alumin - ium electrodes. In order to achieve the maximum removal of pollutants, highlight the key effects of the variables and their simultaneous relationships, full central composite design was applied. Moreover, the backward model selection method using Bayesian Information Criterion and Akaike Information Criterion was carried out to determine the most suitable model with relevant effects. The optimum conditions indicated by the estimated quadratic models were initial pH (5.04), current density (407 A m −2 ), reaction time (74.6 min), and stirring speed (150 rpm), adjusted R 2 of 99.82 %, 99.93 %, and 99.95 % for COD, BOD 5 , and turbidity, respectively. Electrocoagulation was also successful in achieving 90 % COD, 92.3 % BOD 5 , and 99.6 % turbidity removal efficiency. The findings indicated a satisfactory agreement between model forecasts and experimental values.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43196558","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}

{"title":"Transition towards Carbon Footprint Reduction and Energy Intensification in Natural Gas Reforming","authors":"N. Zečević, O. Brasseur","doi":"10.15255/kui.2022.037","DOIUrl":"https://doi.org/10.15255/kui.2022.037","url":null,"abstract":"One of the possible options for carbon footprint reduction in ammonia production is energy intensification of the natural gas reformer furnace. This paper addresses how process modelling and simulation concepts can be combined with proven meth-ods such as minimum energy consumption analysis and heat exchanger networks to identify and optimise the main bottlenecks in natural gas reformer furnaces. The main outcome is finding the best possible reconstruction options for natural gas savings and related CO 2 reduction. The applied method delivered an overall reduction of natural gas of 834 m 3 h −1 or 0.51 GJ with accompanying carbon footprint reduction of 0.026 t CO 2 per ton of NH 3 produced. A large part of EU’s ammonia producers will be able to reach net zero emissions by 2050 by following the policy initiatives of the “Green Deal” thanks to this case study. In addition, it provides the basis for the further execution of other possible non-conventional retrofit measures.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41278613","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}

{"title":"Drying Process of Cement Mortar Composites Reinforced with Cellulosic Fibres: Experiment and Mathematical Modelling","authors":"Amina Lachenani‬, M. Bentchikou, Mouloud Boumahdi, S. Hanini, M. Laidi","doi":"10.15255/kui.2022.010","DOIUrl":"https://doi.org/10.15255/kui.2022.010","url":null,"abstract":"In this paper, six novel mathematical models based on semi-empirical calculus are proposed and applied to characterise the oven-drying process of cement mortar composites reinforced with cellulosic fibres (CMCRCFs). The drying experiments were carried out on four levels of oven-drying temperatures (70, 85, 105, and 120 ° C), with four different cellulosic fibres content (0, 5, 10, and 20 %). Obtained results were compared to those derived by regression analysis of six most typically used math ematical drying models (Newton, Page, Page modified1, Page modified2, Handerson Pabis, and Logarithmic) in addition to six proposed models. The regression accuracy of the drying process was evaluated by the coefficient of determination ( R 2 ), low mean square error (MSE), low root mean squared error (RMSE), and mean absolute error (MAE). Additional criteria were used to ensure more validity of the selected models. The obtained values indicate a highly accurate fit of the proposed model MR9, meaning that the proposed model can clearly interpret the experimental drying data and predict the dry state of CMCRCFs.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48386381","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}

{"title":"Boric Acid Modified Chitosan Scaffolds Chemically Crosslinked by Genipin","authors":"Luka Dornjak, Karla Ostojić, Teodoro Klaser, Inga Urlić, Anamarija Rogina","doi":"10.15255/kui.2022.018","DOIUrl":"https://doi.org/10.15255/kui.2022.018","url":null,"abstract":"Chitosan scaffolds are an effective biologically active material with versatile application in chemistry and medicine. Chitosan is a linear polysaccharide, a derivative of chitin, with great biocompatibility due to the possession of functional groups such as −OH and −NH 2 , which allow for biodegradability and antibacterial function. Chitosan has a polycation nature allowing complex formation with metal ions and many biomolecules such as DNA, proteins and lipids, while its specific structure and functional groups are responsible for antibacterial, hemostatic, and analgesic properties. To improve its angiogenic and antimi- crobial potential, chitosan can be modified by boron (borate ions). The aim of this work was to prepare boric acid modified chitosan scaffolds, using boric acid as a boron precursor, as potential bioactive scaffolds for tissue regeneration. Borate ions tend to form complexes with hydroxyl groups, however, such physical interactions between boron and chitosan functional groups result in poor encapsulation efficiency. To ensure higher boron incorporation, chitosan scaffolds were cross-linked by genipin, a cross linker with lower cytotoxicity in contrast to glutaraldehyde commonly used to prepare stable chitosan-based materials. The degree of deacetylation ( DD ) and concentration of chitosan solution as well as the concentration of a solvent are impor tant parameters that affect the crosslinking process. Moreover, the addition of boric acid could interfere with the crosslinking process by occupying chitosan functional groups. Here, chitosan scaffolds were modified with different concentrations of boric acid, while the concentrations of chitosan solution (1.2 w/v), genipin (2 % w/w), and acetic acid (0.5 % v/v) were kept constant. Obtained scaffolds were characterised by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), differential scanning calorimetry (DSC), Fourier transformation infrared spectroscopy (FTIR), while cytotoxicity was evaluated as a function of materials concentration and exposure time. The results indicated successful incorporation of boron into crosslinked chitosan scaffolds with highly porous structure and low cytotoxicity.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45794730","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}

{"title":"Razdvajanje faza u sustavu La0.5Sr0.5MnO3","authors":"Andreja Žužić, J. Macan","doi":"10.15255/kui.2022.016","DOIUrl":"https://doi.org/10.15255/kui.2022.016","url":null,"abstract":"Perovskites are investigated as potential working materials in new technologies, such as solid ox - ide fuel cells, thermochemical energy storage, and magnetic refrigerators. They are interesting due to their application properties, such as electrical conductivity, ferromagnetic properties, and reducibility. Properties of perovskites can be improved by doping and the formation of structural defects. The aim of this work was to investigate the possibility of preparing Sr-doped lanthanum manganite with the chemical formula La 0.5 Sr 0.5 MnO 3 by coprecipitation procedure, and to analyse the observed phase separation. The material was prepared by procedure in which sources of metal cations (La 3+ , 2+ phase, especially when in tablet form.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43946128","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}

{"title":"Poboljšana ekstrakcija fenolnih spojeva iz kore mandarine primjenom visokonaponskog električnog pražnjenja: Utjecaj procesnih parametara i optimizacija","authors":"Marija Banožić, Silvija Šafranko, Dora Bogadi, K. Aladić, S. Jokić","doi":"10.15255/kui.2022.023","DOIUrl":"https://doi.org/10.15255/kui.2022.023","url":null,"abstract":"","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42543216","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}

{"title":"Combined Application of Membrane and Advanced Oxidation Processes for Removal of Pharmaceuticals from Water","authors":"Josipa Papac Zjačić, Silvia Morović, K. Košutić, D. Ašperger","doi":"10.15255/kui.2022.008","DOIUrl":"https://doi.org/10.15255/kui.2022.008","url":null,"abstract":"The presence of pharmaceuticals in the aquatic environment is problematic in many aspects, mainly due to their specific mode of action, and physical and chemical properties that make them highly resistant to degradation. This new group of contaminants is frequently detected in conventional wastewater treatment plants. Removal of pharmaceuticals from water by primary and secondary methods (filtration, sedimentation, biological treatment) is not satisfactory, therefore advanced methods involving membrane and advanced oxidation processes are increasingly being de -veloped. The most significant advantage of membrane technologies is their wide industrial applicability while maintaining the highest water standards. Advanced oxidation processes can effectively decompose complex pollutants into simpler ones, and mineralize organic pollutants in wastewater without generating secondary waste. In order to improve their advantages, but also to eliminate disadvantages, these technologies are increasingly complemented and combined, resulting in higher efficiency in removing pharmaceuticals from water and reducing their toxicity.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41494741","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}

{"title":"Mjere dezinfekcije i sanitacije u akreditiranom ispitnom laboratoriju – osvrt na COVID-19 infekciju","authors":"Rea Janda, Nataša Mikulec, Damir Andabaka, Ksenija Vitale","doi":"10.15255/kui.2022.015","DOIUrl":"https://doi.org/10.15255/kui.2022.015","url":null,"abstract":"Living and working environments are most often closed spaces where it is necessary to provide health protection for family members and employees. Some activities require special protection, especially during a pandemic. The living and working environments can be kept clean and tidy in three ways: by cleaning, disinfecting, and sanitising. This paper presents a review of the literature linking disinfectants, their use, and resistance of microorganisms to disinfectants. In addition, it gives an overview of critical points that have arisen in various testing laboratories in the Republic of Croatia, related to the COVID-19 pandemic, and as a consequence of the lack of guidelines in norms. The literature search was conducted based on the keyword 'disinfection' in PubMed, Science Direct, Web of Science, Scopus and Google Scholar databases, and on the CDC and HZJZ websites due to the latest recommendations regarding COVID-19 infections. Results have shown that a norm is a basic document that needs a specific upgrade depending on the type of laboratory and its activities, and it should not be an independent decision of each individual laboratory. Based on the identified needs and problems, state institutions should provide detailed instructions depending on the laboratory activity. Therefore, this situation and the experience gained should be used as a starting point for document development that could be applicable in crisis states generally. In addition, it could be used as a basis for education and training in crisis states.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43322462","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}

{"title":"Adsorpcija Zn(II) iona na metalurškom otpadu","authors":"Anita Štrkalj, Luka Mesek, Vesna Ocelić Bulatović, Zoran Glavaš","doi":"10.15255/kui.2022.013","DOIUrl":"https://doi.org/10.15255/kui.2022.013","url":null,"abstract":"adsorption isotherm models. It was found that the Langmuir model is more appropriate, and that adsorption takes place as chemisorption.","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45507981","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}

{"title":"Kauzalni ekološki model sjevernog Jadrana temeljem podataka EU projekta “LTER Northern Adriatic Sea”","authors":"Želimir Kurtanjek","doi":"10.15255/kui.2022.033","DOIUrl":"https://doi.org/10.15255/kui.2022.033","url":null,"abstract":"The aim of this work was to show possibilities of applied artificial intelligence methodologies and structural causal modelling (“Structural Causal Model”, SCM) with the object of gaining a scientific level contribution to the determination of functional causal dependencies in complex ecological systems. In this work, applied was SCM for the determination of dependencies of chlo rophyll concentration on physical and chemical parameters in the northern Adriatic Sea during the period 1965 to 2015. The experimental data are the outcome of the long-term and extensive investigation as a part of the EU project “LTER Northern Adriatic Sea”, and are freely available within the EU Open Science policy. The data are a “Big Data” base with 108 687 samples and 43 descriptors. Proposed is a mathematical model with Bayes network (BN) as a directed acy - clic graph (DAG). The model structure was determined by the Hamilton-Schmidt conditional independence test with a significance level of α = 0.05. The SCM model shows that the direct causal variables for chlorophyll concentration are: temperature, salinity, pH, and concentrations of nitrogen, phosphor, and silica. The BN model was adjusted according to d-separation with the objective to block confounding and contra-causal back door interference. The functions of causal dependencies were determined as the marginal distributions with Bayes network models with a single interior layer for interpolation. The most important causal effect was due to temperature (−0.07 μg chlorophyll A/°C). The model predicted reversed positive causality between chloro phyll concentration and dissolved oxygen (0.2 mg DO 2 /μg chlorophyll A). Also evaluated was nonparametric comparative analysis of chlorophyll and abiotic parameters between Croatian and northern Adriatic Sea (Slovenia and Italy). The comparison was based on median metrics to avoid the pronounced influence of outliers due to hydrodynamic effects. The median concentration of dissolved oxygen in Croatian Adriatic was 5.8 mg O 2 /l, while in Slovenian and Italian 5.5 mg O 2 /l, and the median temperature was T = 14.6 °C compared to T = 15.1 °C. There is a significant difference in the abundance of dinoflagellates in Croatia 3 cell/l, while in Slovenia and Italian 5 cells/l. The difference is more pronounced by the number and values of “hot spots” outliers. The difference between chlorophyll concentrations is not significant (0.65 and 0.90 μg l −1 ); however, the difference in the distribution of the outliers is significant with more frequent and bigger outliers in Italian and Slovenian Adriatic. Also observed was a significant difference in SiO 4 distribution, with higher concentrations in the western Adriatic. The random forest RF decision tree models are applied for the development of the predictive models of biological parameters based on abiotic data. The RF models are validated by 5-fold cross-validation. The models have out-of-box mean relative errors of 6.5 % for chlor","PeriodicalId":43849,"journal":{"name":"Kemija u Industriji-Journal of Chemists and Chemical Engineers","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2022-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46896125","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}