The influence of the chemical modification on the jute structure and properties

U teorijskom delu doktorske disertacije sistematizovani su najnoviji i najrelevantniji literaturni podaci vezani za strukturu, svojstva, upotrebu i reaktivnost vlakna jute. Značajan deo teorijskih razmatranja je posvećen hemijskom modifikovanju lignoceluloznih materijala, sa akcentom na uticaje selektivnog uklanjanja neceluloznih komponenata na njihovu strukturu i svojstva, što predstavlja osnovu za eksperimentalni deo ovog rada. Kao posebne celine u okviru teorijskog dela doktorske disertacije obrađeni su rezultati drugih istraživačkih grupa dobijeni proučavanjem elektro-fizičkih svojstva celuloznih materijala. Takođe, proučeni su literaturni navodi i sistematizovani rezultati dobijeni proučavanjem mogućnosti primene lignoceluloznih materijala za izradu filtera za sorpciju jona teških metala, ali i za izradu antimikrobnih materijala...In the theoretical part of the doctoral dissertation, the latest and the most relevant literature data concerning jute structure, properties, end-uses and reactivity have been systematically reviewed. A significant part of the theoretical considerations is dedicated to lignocellulosic material chemical modifications, with an emphasis on the influence of non-cellulosic components removal on their structure and properties, which represents a basis for the experimental part of this work. The literature data and results obtained by other research groups regarding cellulosic material electro-physical properties represent a significant part of the theoretical considerations. Furthermore, the possibilities of applying lignocellulosic materials as filters in the treatment of heavy metal contaminated industrial effluents and obtaining antimicrobial materials were studied systematically..

Биосорпција јона никла на тканинама од јуте: кинетичка и изотермска испитивања

Raw jute fabric was chemically modified with 1 % NaOH for 30 min, 17.5 % NaOH for 5 min or with 0.7 % NaClO2 for 30 and 60 min to study the influence of changes in the chemical composition of the fabrics and quantity of carboxyl groups on the biosorption capacity of the fabrics for nickel ions. The effects of contact time and initial concentration of nickel ions on the biosorp- tion capacity of the fabrics were also investigated. The obtained results rev- ealed that the biosorption of nickel ions can be explained by the pseudo-sec- ond-order kinetic model, while the experimental isotherm data fit better with the Langmuir model. The calculated ratios between maximal biosorption cap- acity (6.30–12.06 mg g-1) of the jute fabrics and carboxyl group quantity indi- cated that approximately half of the carboxyl groups of the fabrics’ would be involved in binding nickel ions during biosorption. Therefore, the quantity of carboxyl groups can be used to predict the maximal biosorption capacity of jute fabrics toward nickel ions. In the case of oxidized jute fabrics, the lignin rem- oval, and consequently increased content of cellulose and hemicelluloses, also contributed to a higher biosorption capacity.Сирова тканина од јуте је хемијски модификована 1 % NaOH у току 30 min, 17,5 % NaOH у току 5 min или 0,7 % NaClO2 у току 30 и 60 min у циљу испитивања утицаја промена хемијског састава и садржаја карбоксилних група на биосорпциони капацитет тканина према јонима никла. Такође, испитиван је и утицај времена контакта тканина са раствором NiSO4 и почетне концентрације раствора никла на биосорпциони капацитет тканина од јуте. Добијени резултати указују на то да се процес биосорпције никла може описати кинетичким моделом псеудо-другог реда, а равнотежне вредности добијене за сорпцију никла се боље слажу са Langmuir адсорпционом изотермом. Израчунати однос између максималних биосорпционих капацитета тканина од јуте (6,30–12,06 mg g-1) и садржаја карбоксилних група указују на то да ће приближно половина карбоксилних група учествовати у везивању јона никла током биосорпције. Према томе, садржај карбоксилних група се може користити као индикатор максималног биосорпционог капацитета тканина од јуте према јонима никла. Код оксидисане тканине, уклањање лигнина које је праћено са повећањем садржаја целулозе и хемицелулоза је такође допринело већем биосорпционом капацитету

Obtaining colored antioxidant cotton and cotton/linen fabrics using green tea aqueous extract

Green tea aqueous extract was prepared and characterized regarding total flavonoids and total phenolic contents as well as antioxidant activity (assessed by ABTS method). The characterized aqueous extract was used for dyeing and functionalization of 100% cotton and cotton/linen (47%/53% and 70%/30%) fabrics. Fabric color strength (K/S) values and their antioxidant activities before and after washing were compared. The obtained results revealed that 100% cotton (GTI), 47%/53% cotton/linen (GTII), and 70%/30% cotton/linen (GTIII) fabrics have K/S values ranging between 8.33 and 10.85. After one washing cycle, these values decreased significantly. On the other hand, dyed fabrics showed excellent (100 %) ABTS radical scavenging ability which remained excellent (GTII) or decreased to medium (GTI and GTIII) levels after one washing cycle. Based on the obtained results, it can be concluded that 47%/53% cotton/linen fabric is the most suitable for functional clothing capable of trapping the free radial of oxygen species. The current paper represents a step towards a more sustainable textile industry that could undoubtedly contribute to overcoming the environmental problems caused by the textile industry

Addressing the environmental problems of wastewater: reducing the pollution while providing multifunctional wool fabrics

The reduction of water pollution represents one of the priority topics of the EU’s goal to achieve climate neutrality by 2050. Considering this, the concept of reusing the same dyebath for multiple dyeing cycles is proposed. For this purpose, two pyridinium-based azo pyridone dyes with improved solubility and affinity towards different fibers, are used for dyeing wool fabric. It is demonstrated that the dye concentration in wastewater could be reduced up to four times by recirculation of the same dyebath 5 times. The dyed fabrics obtained in each cycle are further characterized regarding color strength (K/S) and ultraviolet protection factor (UPF), while their antioxidant potential is evaluated by ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) test. The results revealed that the proposed concept could be used for obtaining multifunctional wool fabrics by following the principles of sustainable development of reducing the effluent load in wastewater

Obtaining Polysaccharide-Based Fabrics with Improved Moisture Sorption and Dye Adsorption Properties

Featured Application: This work has a potential application in biocarpet engineering, which involves the use of cyanobacterial crusts either in the rehabilitation of damaged land surfaces or to combat desertification. Attempts to apply cyanobacterial crusts have not been completely successful so far because the growth of the initial inoculum requires more moisture than arid and semiarid environments can provide. To accelerate the development of the inoculum, it is necessary to provide additional moisture for the growth of cyanobacterial cells. Controlled water delivery could be achieved by using moisture-retentive material that is applied together with the inoculum in the treatment of damaged surfaces. Biocarpet engineering has the potential to solve not only some problems of damaged surfaces and desertification but also reduce and prevent air and water pollution caused by erosion. Raw jute fabric was treated with 0.5, 1.0, or 2.0% chitosan solution to improve its sorption properties (evaluated through the moisture sorption and adsorption of textile dye Reactive Orange 16 (RO 16)), which are essential for fabric utilization as geo-prebiotic polysaccharide support that should provide the necessary water for the growth of cyanobacterial communities in biocarpet engineering. Chitosan-treated fabrics possessed 39–78% higher moisture sorption values than the untreated ones. Concerning the dye adsorption, with the increase in its initial concentration, the adsorption potential of raw and fabrics treated with 0.5 or 1.0% chitosan solution was increased up to 1.9 times. The dye adsorption onto these fabrics was exothermic and enthalpy driven. By increasing the chitosan solution percentage up to 1.0%, fabric adsorption potential increased up to 2.2 times. An inverse relationship was observed in the case of the fabric treated with 2.0% chitosan solution, its adsorption potential decreased with increasing the initial dye concentration and temperature due to the different dominant binding interactions. Concerning the contact time, dye adsorption onto fabric treated with 1.0% chitosan solution was rapid in the first 2 h, while the equilibrium was attained after 4.5 h. The isotherm and kinetic data were represented by the Langmuir model and the pseudo-second-order kinetic model, respectively

Recovering the Soybean Hulls after Peroxidase Extraction and Their Application as Adsorbent for Metal Ions and Dyes

This study is aimed at extending the soybean hulls' lifetime by their utilization as an adsorbent for metal ions (Cd2+ and Cu2+) and dyes (Reactive Yellow 39 (RY 39) and Acid Blue 225 (AB 225)). ATR-FTIR spectroscopy, FE-SEM microscopy, and zeta potential measurements were used for adsorbent characterization. The effect of the solution's pH, peroxidase extraction, adsorbent particle size, contact time, the pollutant's initial concentration, and temperature on the soybean hulls' adsorption potential was studied. Before peroxidase extraction, soybean hulls were capable of removing 72% Cd2+, 71% Cu2+ (at a pH of 5.00) or 81% RY 39, and 73% AB 225 (at a pH of 3.00). For further experiments, soybean hulls without peroxidase were used for several reasons: (1) due to their observed higher metal ion removal, (2) in order to reduce the waste disposal cost after the peroxidase (usually used for wastewater decolorization) extraction, and (3) since the soybean hulls without peroxidase possessed significantly lower secondary pollution than those with peroxidase. Cd2+ and Cu2+ removal was slightly increased when the smaller adsorbent fraction (710-1000 μm) was used, while the adsorbent particle size did not have an impact on dye removal. After 30 min of contact time, 92% and 88% of RY 39 and AB 225 were removed, respectively, while after the same contact time, 80% and 69% of Cd2+ and Cu2+ were removed, respectively. Adsorption of all tested pollutants follows a pseudo-second-order reaction through the fast adsorption, intraparticle diffusion, and final equilibrium stage. The maximal adsorption capacities determined by the Langmuir model were 21.10, 20.54, 16.54, and 17.23 mg/g for Cd2+, Cu2+, RY 39, and AB 225, respectively. Calculated thermodynamic parameters suggested that the adsorption of all pollutants is spontaneous and of endothermic character. Moreover, different binary mixtures were prepared, and the competitive adsorptions revealed that the soybean hulls are the most efficient adsorbent for the mixture of AB 225 and Cu2+. The findings of this study contribute to the soybean hulls' recovery after the peroxidase extraction and bring them into the circular economy concept

Biosorption of Cu2+ from aqueous solution by alkali modified waste jute woven fabrics

Waste jute fabrics (raw and alkali modified), acquired as waste from different industries were used as an efficient biosorbent for removal of Cu2+ ions from aqueous solution. All woven jute fabrics (raw as well as alkali modified) were characterized by determination of their chemical composition and amount of carboxyl groups. The effect of solution pH, contact time and initial metal ion concentration on the biosorption were studied. The alkali modifications lead to hemicelluloses removal and an increased amount of carboxyl groups. The maximum biosorption capacity for Cu2+ was observed at pH 5.5. Concerning the contact time, more than 80% of total Cu2+ uptake by the raw jute fabric was removed within 1 h. On the other hand, in the case of alkali modified jute fabrics, between 70-75% of the total Cu2+ uptake was removed within 3 h. Increased initial ion concentration from 10 to 20 mg/l caused an increase in the total uptake capacity of alkali modified jute fabrics for 42-55%. It was found that the biosorption properties of waste jute fabrics are predominantly influenced by the amount of carboxyl groups, while fabric chemical composition (i.e. hemicelluloses content) has a secondary role in the biosorption of Cu2+ ions. The best biosorption performance possesses alkali modified jute fabric with 58% higher amount of carboxyl groups; its total uptake capacity towards Cu2+ ions (at 20 mg/l) is about 2 times higher compared to the raw jute fabric

Poli(laktid-ko-glikolid) mikročestice kao sustav za kontrolirano oslobađanje proteina: priprava i karakterizacija

Poly(DL-lactide-co-glycolide) (PDLLGA) and poly(L-lactide-co-glycolide) (PLLGA) copolymers were prepared by bulk ring opening polymerization of lactide and glycolide and characterized by GPC, FTIR, 1H NMR and DSC. Copolymers with different molar masses at a constant lactide/glycolide ratio were used for preparation of bovine serum albumin (BSA)-loaded microparticles by the double emulsion w/o/w method. The influence of the copolymer molar mass and composition on the microparticle morphology, size, yield, degradation rate, BSA-loading efficiency and BSA release profile were studied. For microparticles prepared from PDLLGA copolymers, a biphasic profile for BSA release was found and for those made from PLLGA copolymers the release profile was typically triphasic; both of them were characterized by high initial burst release. Possible reasons for such behavior are discussed.Poli(DL-laktid-ko-glikolid) (PDLLGA) i poli(L-laktid-ko-glikolid) (PLLGA) kopolimeri priređeni su polimerizacijom laktida i glikolida uz otvaranje prstenova i karakterizirani pomoću GPC, FTIR, 1H NMR i DSC. Kopolimeri različitih molarnih masa i stalnog omjera laktida i glikolida upotrebljeni su za pripravu mikročestica s goveđim serumskim albuminom (BSA) metodom dvostruke emulzije tipa voda/ulje/voda. Proučavan je utjecaj molarne mase i sastava kopolimera na oblik, veličinu, iskorištenje i stupanj razgradnje mikročestica, uklapanje i oslobađanje BSA. Za mikročestice pripravljene s PDLLGA kopolimerom utvrđen je bifazični profil oslobađanja BSA, a za mikročestice s PLLGA kopolimerom trifazičan profil. Za obje vrste karakteristično je brzo početno oslobađanje. Razmatrani su mogući uzroci takvog ponašanja

Инсулинска резистенција и метаболичен синдром кај хепатитис Ц вирус серонегативни хероински зависници

Initial studies on impaired glucose-insulin homeostasis in heroin dependents have not defined the impact of concomitant hepatitis C infection (HCV), which has been  strongly associated with the development of insulin resistanceand metabolic syndrome (MS). The aim of our study was to evaluate the association of heroin dependence with glucose-insulin homeostasis and MS in heroin dependents with HCV seronegativity. Materials and methods: The study was prospective and cross-sectional, including 160 heroin dependents compared to a control group of 60 participants.MS was diagnosed using International Diabetes Federation criteria. The homeostatic model assessment for insulin resistance (HOMA-IR) and pancreatic β-cell function (HOMA-%B) were used for assessing insulin resistance and β-cell function of pancreas. Results: MS was detected in 9.32% of heroin addicts. Heroin dependents with MS compared to dependents without MS were older, had higher BMI, waist circumference and significantly higher systolic and diastolic blood pressure, increased triglycerides (F=8.233, df=2, p<0.001), apoB (F=8.154, df=2, p=0.001), and reduced HDL-C (F=25.926, df=2, p<0.001) and apoA-I (F=16.406, df=2, p<0.001), significantly increased inuslinemia (F=4.928, df=2, p<0.05), insulin resistance-HOMA-IR (F=4,928, df=2, p<0,05) and insignificantly increased pancreatic β-cell function (194.66 ±224.05) (F=2.461, df=2, p>0.05). Conclusions: Insulin resistance and МS, independent of HCV, was also registered in heroin dependence. Timely recognition will enable more successful treatment of comorbidities and illicit drug dependence.Првичните студии за нарушена глукозно-инсулинска хомеостаза кај хероински зависници не го дефинираа и влијанието на  хепатитис Ц инфекцијата (ХЦВ), којa е силно поврзана со развој на инсулинска резистенција и метаболичен синдром (МС). Целта на нашата студија беше да ја процени поврзаноста на зависноста од хероин со глукозно-инсулинската хомеостаза и МС кај хероински зависници кои се ХЦВ серонегативни. Материјали и методи: Студијата беше проспективна и пресечна, вклучувајќи 160 хероински зависници и контролна група од 60 испитаници. МС беше дијагностициран според критериумите на Меѓународната федерација за дијабетес. За проценка на инсулинската резистенција и функцијата на β-клетките на панкреасот беше користен хомеостатскиот модел за инсулинска резистенција (HOMA-IR) и функцијата на β-клетките на панкреасот (HOMA-%B). Резултати: МС беше детектиран кај 9,32% од хероинските зависници и тие во споредба со зависниците без МС беа постари, со повисок БМИ, обем на половината и значително повисок систолен и дијастолен крвен притисок, покачени триглицериди (F=8, 233, df=2, p<0,001), apoB (F=8,154, df=2, p=0,001), и намалени HDL-C (F=25,926, df=2, p<0,001) и apoA-I (F=16,406, df=2, p<0,001), со значително зголемена инсулинемија (F=4,928, df =2, p<0,05), инсулинска резистенција – HOMA-IR (F=4,928, df=2, p<0,05) и незначително зголемена функција на β-клетките на панкреасот (194,66 ±224,05) (F=2,461, df=2, p>0,05). Заклучок: Инсулинската резистенција и МС, независно од ХЦВ инфекција, се регистрира и кај хероинската зависност. Навременото препознавање ќе овозможи поуспешен третман на коморбидитетите и на болеста на зависноста од илегални дроги