Materials Science and Applied Chemistry最新文献

{"title":"Effect of humic-rich peat extract on plant growth and microbial activity in contaminated soil / Ar humusvielām bagāta kūdras ekstrakta ietekme uz augu augšanu un mikroorganismu aktivitāti piesārņotā augsnē","authors":"Olga Muter, Baiba Limane, Silvija Strikauska, Māris Kļaviņš","doi":"10.1515/msac-2015-0012","DOIUrl":"https://doi.org/10.1515/msac-2015-0012","url":null,"abstract":"Abstract The aim of this work was to compare the effect of 1 % and 5 % humic substances (HS) on the growth of bean, wheat, rape and cress, as well as microbial activity (respiration, enzyme activity) in sandy loam soil spiked with a complex contamination, derived from municipal waste. The results of 23 days pot vegetation experiment demonstrated the stimulating effect of HS on the plant growth and soil microbial activity. Humusvielu kūdras ekstrakts (HKE), kas satur augu un dzīvnieku valsts sadalīšanās produktus, raisa lielu zinātnisko interesi augsnes auglības un revitalizācijas jomā. Darbā izmantojamais HKE tika iegūts kūdras ekstrakcijas rezultātā saskaņā ar standarta metodi. Kūdras humīnskābes satur C 52 %; H 5 %, N 1.6 %, S 0.5 %, О - 32-43 %, pelnus 2 %. Iegūtie rezultāti pēc Van-Klevelena metodes liecināja, ka analizējamais materiāls ir organisko vielu sadalīšanās sākotnējā stadijā. Eksperiments tika veikts laboratorijas apstākļos 23 dienas kultivējot kviešus, pupas, rapsi un kressalātus. Eksperimentiem izmantota smilšmāla augsne, kas iegūta municipālo atkritumu glabātuves apkārtnē. Katrā izmēģinājuma traukā bija 32 g (50 ml) augsnes, 0,5 ml (1 tilp. %) vai 2.5 ml (5 tilp. %) HKE, kā arī 20 ml toksiska infiltrāta, kas iegūts atkritumu glabāšanas vietā. Visu testējamo augu virszemes daļas biomasas pieaugums bija lielāks variantos ar nepiesārņoto augsni. HEK pievienošana stimulēja pupiņu un kressalātu sakņu sistēmas attīstību nepiesārņotā augsnē, bet kviešiem un rapsim - piesārņotā augsnē. HEK stimulējošā ietekme uz augsnes mikroorganismiem tika novērota variantos ar kviešiem, pupiņām un rapsi. Statistiski ticami iegūti ureāzes aktivitātes palielināšanās rezultāti piesārņotā augsnē ar HEK piedevu kviešiem (p = 0.005) un rapsim (p = 0.027). Variantā ar kressalātiem HEK nomāc mikroorganismu ureāzes un fluoresceīna diacetāta aktivitāti. Variantos ar rapsi HEK pievienošana piesārņotai augsnei ievērojami stimulēja augsnes mikrofloras substrāta inducēto elpošanu. Tādejādi HEK ietekmi uz testējamo augu augšanu un augsnes mikroorganismu aktivitāti var novērtēt kā sugasspecifisku. Iegūtie rezultāti liecina, ka HEK efekts ir atkarīgs no augsnes piesārņojuma un humātu iedarbības izraisītā mehānisma komplicēto fizikāli-ķīmisko un bioloģisko procesu kopumā. Optimālai HEK izmantošanai biotehnoloģiskajos procesos augsnes kvalitātes uzlabošanā ir nepieciešami tālāki pētījumi.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"26 1","pages":"68 - 74"},"PeriodicalIF":0.0,"publicationDate":"2015-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90354614","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":"Toxicity Evaluation of Surface Cleaning Preparation Using Different Test Methods / Virsmu tīrīšanas līdzekļa toksiskuma novērtēšana, izmantojot dažādas testa metodes","authors":"Dagnija Vecstaudza, Māris Kļaviņš, Olga Muter, R. Rutkis","doi":"10.1515/msac-2015-0014","DOIUrl":"https://doi.org/10.1515/msac-2015-0014","url":null,"abstract":"Abstract Surface cleaning preparations pose a serious threat to the environment. Toxicity of a pre-manufactured preparation SCP-1 was tested on bacteria, algae and higher plants and was expressed as a minimal inhibitory concentration (MIC). Obtained results showed that among unicellular and more complex testorganisms MIC values differed 10-100 fold suggesting that an application of complex test-organism battery is necessary to evaluate the toxicity of SCP-1 thoroughly. MIC values were different from the critical micelle concentration; this indicates that the SCP1 mechanism of action might not involve membrane disruption and/or destabilization. Virsmu tīrīšanas līdzekļi ir būtiski vides piesārņotāji. Svarīgs posms jaunu tīrīšanas līdzekļu testēšanā ir to toksiskās ietekmes novērtēšana ar dažādiem testa organismiem un metodēm. Šajā pētījumā veikts virsmu tīrīšanas līdzekļa SCP-1 toksiskuma novērtējums, izmantojot vairākus testa organismus: Gram-negatīvām baktērijām (Pseudomonasfluorescens AM11 kultūru, Pseudomonas spp. un Stenotrophomonas spp. celmiem konsorcija sastāvā), saldūdens aļģēm Selenastrum capricornutum,, žaunkājvēžiem Thamnocephalus platyurus, augstākajiem augiem - kviešiem Triticum spp. un kressalātiem Lepidium sativum). Kā toksiskuma rādītājs tika izvēlēta SCP-1 minimālā inhibējošā koncentrācija (MIK). Iegūtie rezultāti norāda uz MIK atkarību no testa organisma sugas. MIK vērtības savā starpā atšķiras 5-600 reizes - no 0.001 % testa organismam T. platyurus līdz 0.6 % kviešiem un kressalātiem. Piesārņotāju koncentrācijas var sasniegt dažādus līmeņus atkarībā no to fizikāli ķīmiskajām īpašībām un apkārtējās vides īpatnībām. Rezultāti apstiprina nepieciešamību ekotoksikoloģiskos pētījumos izmantot testa organismu bateriju, kas satur dažādu trofisko līmeņu pārstāvjus. Virsmaktīvo vielu toksiskums bieži tiek saistīts ar to kritisko micelāro koncentrāciju (KMK), t. i., vielas koncentrāciju, kurā vielas molekulas veido micellas. Korelācijas cēlonis ir virsmaktīvo vielu izraisītā šūnu membrānu destabilizācija. Pētāmā preparāta KMK ir 0.17 %. Veikto eksperimentu rezultāti neapstiprina viennozīmīgu KMK ietekmi uz SCP-1darbības mehānismu testa organismos.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"os-22 1","pages":"80 - 84"},"PeriodicalIF":0.0,"publicationDate":"2015-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87203511","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":"Effect of Illite Clay Additive on Sintering, Phase Composition and Properties of Mullite-ZrO2 Ceramics / Illītu mālu piedevas ietekme uz mullīta-ZrO2 keramikas saķepšanu, fāžu sastāvu un īpašībām.","authors":"G. Sedmale, Inga Raubiska, A. Krumina, A. Hmelov","doi":"10.1515/msac-2015-0004","DOIUrl":"https://doi.org/10.1515/msac-2015-0004","url":null,"abstract":"Abstract This study focuses on the influence of illite clay on changes of ZrO2 modifications after sintering and consolidation of mullite-ZrO2 ceramics with or without Y2O3 additive. It was found that mullite-ZrO2 ceramics both with 4.5 % Y2O3 additive or without it in presence of illite clay tend to have increased densification and compression strength after sintering. Presence of illite clay also promotes change of ZrO2 monoclinic phase to tetragonal phase and the presence of Y2O3 promotes change to ZrO2 cubic phase. Mullīts ir viena no svarīgākajām augsttemperatūras kristāliskajām fāzēm. Mullīta veidošanās keramikā, tajā skaitā arī keramikā, kas satur ZrO2, nodrošina tai augstas mehāniskās, ķīmiskās un termiskās īpašības, arī pie paaugstinātām temperatūrām. Lai gan mullīta fāze sāk veidoties jau ~ 1000 °C temperatūrā, blīvu mullīta keramikas materiālu parasti iegūst viena cikla saķepināšanas procesā pie paaugstinātas temperatūras (≥ 1400 °C). Lai veicinātu šīs keramikas saķepšanu un saķepšanas temperatūras pazemināšanu, pielieto piedevas vai arī aktīvus pulverus, piemēram, γ-Al2O3 nanopulveri, kvarca smiltis, u.c. Dotajā darbā ir pētīta illīta nanopulvera ietekme uz mullīta-ZrO2 keramikas (ar Y2O3 piedevu un bez tās) sablīvēšanos saķepšanas procesā, iegūtā keramikas materiāla kristālisko fāžu sastāvu un īpašībām. Darbā ir pielietoti divu veidu pulveru maisījumi, kas sastāv no γ-Al2O3, SiO2, ZrO2 (monoklīns), ar Y2O3 piedevu vai bez tās. Katrai maisījumu grupai pievienots illīts 5 %, 10 % vai 15 % (masas daļas). Izejas pulveru morfoloģijas izpētei pielietots elektronmikroskops Hitachi-TM3000 un diferenciāli termiskai analīzes iekārta Setaram, Setsys Evolution 1750. Paraugi formēti disku un cilindru veidā. Saķepināšana veikta divās maksimālajās temperatūrās - 1400 °C vai 1500 °C. Keramikas fāžu sastāvs noteikts pielietojot Rentgena staru difraktometriju (D8 Advance Bruker). Raksturīgās keramikas īpašības (relatīvais blīvums, sarukums) noteiktas izmantojot EN, spiedes izturība noteikta pielietojot iekārtu Toni-Technic. Ir iegūti rezultāti, kas parāda, ka saķepināto keramikas paraugu sablīvēšanās (relatīvais blīvums un sarukums) pakāpe pieaug ar illīta mālu piedevu līdz 10%. Pie lielākas piedevas (15 %) ir vērojama iekšējo poru veidošanās tendece. Savukārt Y2O3 piedeva, it sevišķi illītu mālu klātienē veicina sablīvēšanos saķepināšanas procesā, it seviķi pie 1500 ºC. Ir jāatzīmē arī, ka mālu klātiene veicina ZrO2 monoklīnās modifikācijas transformāciju tetragonālā, bet vienlaicīga mālu un Y2O3 piedevu klātiene savukārt ZrO2 monoklīno modifikāciju tranformē kubiskā modifikācijā.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"10 1","pages":"23 - 26"},"PeriodicalIF":0.0,"publicationDate":"2015-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85488775","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":"Synthesis and Properties of ZnO/Al Thin Films Prepared by Dip-Coating Process","authors":"I. Juhņeviča, Marija Mašonkina, G. Mežinskis, Aļona Gabrene","doi":"10.7250/MSAC.2015.006","DOIUrl":"https://doi.org/10.7250/MSAC.2015.006","url":null,"abstract":"In this work sol–gel dip-coating technique was used to synthesize ZnO and ZnO/Al films. The influence of annealing regime and dopant concentration on the structural properties of ZnO and aluminum doped ZnO (ZnO/Al) films was investigated. The surface morphology and crystallinity of ZnO films were determined using atomic force microscopy and Xray diffraction, respectively. The experimental results show that ZnO and ZnO/Al films prepared using “shock” conditions have smooth surfaces and uniform grains. Increase of aluminum concentration led to grain size reduction and denser film.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"108 1","pages":"33-38"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74643564","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":"Synthesis and Application of Nanoporous Activated Carbon in Supercapacitors","authors":"A. Volperts, G. Dobele, J. Ozoliņš, Ņ. Mironova-Ulmane","doi":"10.7250/MSAC.2015.003","DOIUrl":"https://doi.org/10.7250/MSAC.2015.003","url":null,"abstract":"Influence of the thermocatalytical synthesis on the formation of the porous structure and the properties of microporous carbon wood-based materials was shown. It was found that increase of activation temperature and addition ratio of alkali activator can be used to control not only total pore volume, but also micropore and mesopore proportion. The results of tests on the synthesized carbon materials as electrodes in supercapacitors are shown, as well as the influence of properties of the porous structure of carbon materials on working characteristics of electrodes. It was shown that the increase of activation temperature from 600 °C to 800 °C led to an increased proportion of mesopores in the porous structure; this negatively influencen the cell capacity of the supercapacitor. It was found that the most feasible way of production of activated cabons for the use as electrodes in supercapacitors with sulphuric acid-based electrolyte is low-temperature activation.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"532 1","pages":"16-20"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78159407","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":"Woven Structures from Natural Fibres for Reinforcing Composites","authors":"A. Bernava, Māris Maniņš, G. Strazds","doi":"10.7250/MSAC.2015.005","DOIUrl":"https://doi.org/10.7250/MSAC.2015.005","url":null,"abstract":"The increase of production of woven structures from natural fibres for reinforced composites can be noticed in different sectors of economy. This can be explained by limited sources of raw materials and different environmental issues, as well as European Union guidelines for car manufacture [4]. This research produced 2D textile structures of hemp yarn and polypropylene yarn and tested the impact of added glass fibre yarn on the mechanical properties of the woven structures and the composites produced from them. The woven structures were manufactured using hand looms or industrial looms (CТБ-175) using one layer technique. The mechanical testing of the reinforcements showed that the parameters of the looms had significant impact on the properties of the reinforcements. However, the desired improvement of strength by adding glass fibre to the fabric was not achieved. The one, two, three and four layer composites were produced in a hydraulic press using reinforcements woven from hemp yarn and polypropylene yarn. The mechanical testing of composites showed that the tensile strength of the composites and the tensile stress at maximum load depends on number of the reinforcement layers, but the tensile extension of the composites and the modulus of elasticity are not closely related to the number of reinforcement layers, but rather on elasticity of yarn used in weaving. Swelling of composites in water was detected.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"46 1","pages":"27-32"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77283784","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":"Synthesis and Applications of (-)-(S)-3-Aminoquinuclidine- Derived Thiourea","authors":"Evija Rolava, M. Turks","doi":"10.7250/MSAC.2015.002","DOIUrl":"https://doi.org/10.7250/MSAC.2015.002","url":null,"abstract":"A synthesis of enantiopure thiourea organocatalyst based on (-)-(S)-3-aminoquinuclidine dihydrochloride was developed with quantitative product yield. The catalyst was tested in different reactions: asymmetric Michael addition of ketones and malonates to nitroalkenes, nitromethane 1,4-addition to trans-chalcone, and Friedel-Crafts alkylation of indoles with trans-β-nitrostyrene. The novel thiourea proved to catalyze the aforementioned reactions and expected products were obtained in mediocre yields and low enantioselectivities.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"26 1","pages":"10-15"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75905849","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":"Preparation and Characterization of Porous Titania Ceramic Scaffolds","authors":"Inga Narkevica, Laura Stradiņa, V. Yakushin, J. Ozoliņš","doi":"10.7250/MSAC.2015.001","DOIUrl":"https://doi.org/10.7250/MSAC.2015.001","url":null,"abstract":"Biocompatible ceramics have recently attracted increasing attention as porous scaffolds that stimulate and guide natural bone regeneration. Due to excellent biocompatibility of titania (titanium dioxide or TiO2) porous three-dimensional (3D) TiO2 structures have been proposed as promising scaffolding materials for inducing bone formation from the surrounding environment and for enhancement of vascularisation after implantation. In this paper, 3D porous TiO2 ceramic scaffolds were produced via polymer foam replica method. This work deals with several important issues that are considered to be important for 3D scaffolds applied to regenerate bone tissue: pore size, porosity and mechanical strength. TiO2 ceramic scaffolds with pore size 300 μm − 700 μm and porosity > 90 % were obtained. Scaffolds showed fully open and interconnected pore structure that remained after recoating them with low viscosity TiO2 slurry. By optimising thermal treatment conditions grain growth and collapse of struts could be controlled in a way that resulted in higher compressive strength. Recoating greatly improved compressive strength and it reached 0.74±0.08 MPa after two coatings without causing changes in the open porestructure.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"40 1","pages":"5-9"},"PeriodicalIF":0.0,"publicationDate":"2015-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80661197","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":"Immobilization and Survival of Root Nodule Bacterium Rhizobium leguminosarum Biovar viciae / Gumiņbaktērijas Rhizobium leguminosarum biovar viciae imobilizācija un dzīvotspēja","authors":"Signe Žvagiņa, Zaiga Petriņa, Vizma Nikolajeva, A. Lielpētere","doi":"10.1515/msac-2015-0013","DOIUrl":"https://doi.org/10.1515/msac-2015-0013","url":null,"abstract":"Abstract Rhizobium leguminosarum biovar viciae is a bacterium, which can establish nodules on roots of legumes. Rhizobial inoculants are used in agriculture as bio-fertilizers. Peat, clay powder and three kinds of expanded clay were tested for the immobilization of bacteria. The results showed that carrier material influences the success of immobilization and that storage temperature influences the survival. The best results were achieved with maintenance of bacteria in a suspension and immobilization on peat. We recommend storage of rhizobial products at a temperature of −18 °C or 4 °C. Rhizobium leguminosarum biovar viciae ir augsnes baktērija, kas spēj veidot gumiņus uz zirņu, pupu, lēcu un vīķu saknēm un saistīt atmosfēras slāpekli simbiozē ar augiem. Gumiņbaktērijas izmanto lauksaimniecībā kā bioloģiskus mēslošanas līdzekļus augu augšanas veicināšanai. Komerciālos gumiņbaktēriju preparātus var iegādāties sausā, šķidrā vai liofilizētā formā. Parasti izmanto sausos sagatavotos mēslošanas līdzekļus uz kūdras bāzes. Šī pētījuma mērķis bija imobilizēt R. leguminosarum un noteikt tās dzīvotspēju šķidrumā un dažādos nesējmateriālos, lai izstrādātu uzlabotus gumiņbaktēriju preparātus. Imobilizēšanai izmantoja piecus sterilizētus materiālus: kūdru, māla pulveri, divu veidu ovālus šūnainās keramikas agregātus un cilindriskas keramikas granulas, kas izgatavotas no Planču depozīta Devona perioda māla. Imobilizāciju veica 2,5 stundu laikā 20 °C temperatūrā. Vēlāk kūdru, pulveri un granulas noberza un sasmalcināja ūdenī ar sterilu piestiņu, lai atdalītu pielipušās baktērijas. Baktēriju kolonijas veidojošo vienību skaitu noteica, izsējot iegūto suspensiju atšķaidījumus Petri traukos ar agarizētu barotni. Dzīvotspēju noteica arī ar LIVE/DEAD epifluorescences metodi. Iegūtie rezultāti parādīja, ka nesējmateriāls ietekmē imobilizācijas sekmes un ka uzglabāšanas temperatūra ietekmē R. leguminosarum dzīvotspēju. Vislabākos rezultātus ieguva, uzglabājot baktērijas suspensijā vai imobilizējot uz kūdras. Rekomendējam uzglabāt R. leguminosarum produktus −18 °C vai 4 °C temperatūrā.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"8 1","pages":"75 - 79"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73900470","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":"Use of Differential Treatment of Illite to Modify Their Structure and Properties / Diferencētas apstrādes pielietojums illītu struktūras un īpašību modificēšanai","authors":"G. Sedmale, Mārtiņš Randers, Līga Grase, Juris Kostjukovs","doi":"10.1515/msac-2015-0003","DOIUrl":"https://doi.org/10.1515/msac-2015-0003","url":null,"abstract":"Abstract Influence of chemical, mechanical and thermal treatment on structure and properties of illite and impact on development of high-temperature ceramics was investigated. The object of this study was illite from Quartenary glacio-limnic clay of state importance deposit Apriki. Treated clay fractions were subjected to X-ray diffraction, SEM and differential thermal analysis. It was found that thermal and chemical treatment is effective. Thermally treated illite with Al(OH)3 additive was used for sintering a new dense ceramic compositions. Ceramics were characterized by bulk density, shrinkage and compressive strength 150−165 N/mm2. Pētīta ķīmiskas, mehāniskas un termiskas apstrādes ietekme uz illītu struktūras un īpašību izmaiņām, kā arī šīs apstrādes nozīme blīvu augsttemperatūras keramiko materiālu izstrādē. Par izpētes objektu bija izvēlēti kvartāra māli no Apriķu atradnes, kas ir valsts nozīmes māla atradne. Māli no šīs atradnes ir pieskaitāmi pie karbonātus mazsaturošiem māliem un tiem ir relatīvi augsts mālainās frakcijas saturs (daļiņas ar izmēru < 0,005 μm). Mālu frakciju (illīti/kaolinīts) izdalīja no māliem, pielietojot sedimentācijas un ķīmisko metodi. Pētījumiem pielietota ķīmiski izdalītā mālu frakcija. Šīs frakcijas ķīmiskai apstrādei ir pielietots 3 M un 6 M NaOH ūdens šķīdums, mehāniskai apstrāde bija 24 hilga intensīva malšana planetārajās dzirnaviņās, termiskā - izkarsēšana 600 °C temperatūrā 30 min. Neapstrādāto un apstrādāto illītu raksturojumam pielietoja rentgena fāžu analīzi (XRD modelis Rigaku, Japāna un D8 Advance Bruker AXS). Elelementu/oksīdu analīzi veica ar XRD spektrometru (S4 PIONEER Bruker AXS). Daļiņu morfoloģijas un sastāva izmaiņu izpētei pielietoja skenējošo elektronmikroskopu Nova- Nano 650 (FEI Netherlands). Diferenciāli termiskā fāžu pāreju analīzi veica ar iekārtu Setaram, SETSYS Evolution-1750. Ir parādīts, ka sedimentāri un ķīmiski izdalīto illītu/kaolonīta fāžu sastāvs, kā arī oksīdu analīze ir nedaudz nobīdīti. Bija vērojamas arī daļiņu morfoloģijas atšķirības - sedimentēto illītu plākšņveida morfoloģija bija izteiktāka nekā ķīmiski iegūto. Rentgena fāžu analīze rāda, ka saistībā ar intensīvi malto un ar 3 M NaOH šķīdumu apstrādāto illītu/ kaolinīta fāžu difrakcijas maksimumu izmaiņas ir niecīgas. Maz izmaiņu novēroja arī DTA rezultātos. Savukārt, termiski apstrādātie illīti ir daļēji destrukturēti, pie ~ 600 °C izdalījās struktūras OH- grupas. Izmaiņas pēc apstrādes ar 6 M NaOH šķīdumu arī ir attiecināmas uz illītu struktūras izmaiņām, veidojoties nātrija alumosilikāta hidrātam Na(AlSiO4)6·H2O, kurš, cauraužot illītus, tos “sacementē”. Termiski apstrādātie illīti ir aprobēti kā saķepšanu veicinošs komponents jaunu keramikas kompozīciju izveidošanai ar Al(OH)3. Ir parādīts, ka 60 masas % termiski apstrādātu illītu piedeva pie Al(OH)3 apdedzināšanas temperatūrā > 1050 °C veido blīvu keramikas materiālu ar augstu spiedes izturības vērtību - 168 N/mm2.","PeriodicalId":18239,"journal":{"name":"Materials Science and Applied Chemistry","volume":"7 1","pages":"19 - 22"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80722365","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}