Uticaj anjona na uklanjanje boja iz otpadnih voda tekstilne industrije

Textile industry wastewater represents a serious environmental problem because it contains different dyes and toxic substances used during the production and dyeing of textile. Thus, it is necessary to investigate the removal of dyes from wastewater using a simple method such as sorption. Since different salts are used during the dyeing of textile, anions and cations are present in wastewaters and they can affect the process of dye removal. In this paper, the influence of several anions on the removal of textile dyes was investigated. Chitosan and methacrylic acid-based hydrogels obtained by free-radical polymerization and cross-linked with N,N'-methylenebisacrylamide were used as sorbents. Removal of two textile dyes was investigated (anionic dye C.I. Acid Orange 7 and cationic dye C.I. Basic Red 1) at two different temperatures (25 and 50 ° C). The influence of anions on the removal was evaluated using sodium compounds dissolved in dye solutions (NaCl, CH3COONa, Na2CO3, Na2HPO4, NaH2PO4, NaNO3, NaOH). It has been found that hydrogel degree of swelling increased significantly with the increase of pH of the dye solution. The presence of different ions affected the sorption capacity of hydrogels and the best results were obtained when NaH2PO4 and NaNO3 were present.Otpadne vode tekstilne industrije predstavljaju ozbiljan ekološki problem, jer u sebi sadrže različite boje i toksične supstance koje se upotrebljavaju tokom proizvodnje i bojenja tekstila. Stoga, potrebno je da se ispita mogućnost uklanjanja boja iz otpadnih voda tekstilne industrije jednostavnom metodom sorpcije. Kako se u procesu bojenja tekstila koriste različite soli, u ovim otpadnim vodama često su prisutni anjoni i katjoni koji mogu da utiču na sam proces uklanjanja boja. U ovom radu analiziran je uticaj nekoliko anjona na uklanjanje boja za tekstil pomoću hidrogelova na bazi hitozana. Korišćeni hidrogelovi su kopolimeri hitozana i metakrilne kiseline dobijeni slobodno-radikalskom polimerizacijom, a kao umreživač je upotrebljen N,N’-metilenbisakrilamid. Anjonska boja C.I. Acid Orange 7 i katjonska boja C.I. Basic Red 1 su korišćene u model vodama, a uklanjanje boja je izvedeno na dve različite temperature (25 i 50 C). Uticaj anjona je ispitan dodatkom natrijumovih jedinjenja u rastvore boja (NaCl, CH3COONa, Na2CO3, Na2HPO4, NaH2PO4, NaNO3, NaOH). Utvrđeno je da hidrogelovi izrazito bubre sa povećanjem pH rastvora. Prisustvo različitih jona utiče na kapacitet sorpcije, a najbolji rezultati su dobijeni kada su u rastvoru prisutne soli NaH2PO4 i NaNO3

Uticaj anjona na uklanjanje boja iz otpadnih voda tekstilne industrije

Textile industry wastewater represents a serious environmental problem because it contains different dyes and toxic substances used during the production and dyeing of textile. Thus, it is necessary to investigate the removal of dyes from wastewater using a simple method such as sorption. Since different salts are used during the dyeing of textile, anions and cations are present in wastewaters and they can affect the process of dye removal. In this paper, the influence of several anions on the removal of textile dyes was investigated. Chitosan and methacrylic acid-based hydrogels obtained by free-radical polymerization and cross-linked with N,N'-methylenebisacrylamide were used as sorbents. Removal of two textile dyes was investigated (anionic dye C.I. Acid Orange 7 and cationic dye C.I. Basic Red 1) at two different temperatures (25 and 50 ° C). The influence of anions on the removal was evaluated using sodium compounds dissolved in dye solutions (NaCl, CH3COONa, Na2CO3, Na2HPO4, NaH2PO4, NaNO3, NaOH). It has been found that hydrogel degree of swelling increased significantly with the increase of pH of the dye solution. The presence of different ions affected the sorption capacity of hydrogels and the best results were obtained when NaH2PO4 and NaNO3 were present.Otpadne vode tekstilne industrije predstavljaju ozbiljan ekološki problem, jer u sebi sadrže različite boje i toksične supstance koje se upotrebljavaju tokom proizvodnje i bojenja tekstila. Stoga, potrebno je da se ispita mogućnost uklanjanja boja iz otpadnih voda tekstilne industrije jednostavnom metodom sorpcije. Kako se u procesu bojenja tekstila koriste različite soli, u ovim otpadnim vodama često su prisutni anjoni i katjoni koji mogu da utiču na sam proces uklanjanja boja. U ovom radu analiziran je uticaj nekoliko anjona na uklanjanje boja za tekstil pomoću hidrogelova na bazi hitozana. Korišćeni hidrogelovi su kopolimeri hitozana i metakrilne kiseline dobijeni slobodno-radikalskom polimerizacijom, a kao umreživač je upotrebljen N,N’-metilenbisakrilamid. Anjonska boja C.I. Acid Orange 7 i katjonska boja C.I. Basic Red 1 su korišćene u model vodama, a uklanjanje boja je izvedeno na dve različite temperature (25 i 50 C). Uticaj anjona je ispitan dodatkom natrijumovih jedinjenja u rastvore boja (NaCl, CH3COONa, Na2CO3, Na2HPO4, NaH2PO4, NaNO3, NaOH). Utvrđeno je da hidrogelovi izrazito bubre sa povećanjem pH rastvora. Prisustvo različitih jona utiče na kapacitet sorpcije, a najbolji rezultati su dobijeni kada su u rastvoru prisutne soli NaH2PO4 i NaNO3

Sorption of textile dyes from textile wastewater by chitosan-based hydrogel

With the excessive risks that are present in today's environment, it is of great importance to treat wastewaters before their discharge in water streams. One of the everyday challenges is design of a low-cost and environmentally friendly sorbent such as hydrogel based on chitosan, itaconic and methacrylic acid that can remove wide range of textile dyes. In the present study, this hydrogel has been utilized for investigation of removal of three different azo dyes from simulated textile wastewater: C.I. Basic Blue 9, C.I. Basic Red 1 and C.I. Acid Orange 7. It was found that pH value of the solution had significant effect on dye sorption. Removal of basic dyes was successful at higher pH values, while sorption of acid dye was possible only at low pH value of solution. Simulated textile wastewater is a complex system with various salts, acids and polymers present beside dyes. Regardless of these components, excellent sorption capacity was achieved (more than 80% of dyes were removed), which makes this hydrogel attractive for use under real conditions

Ultrazvučna ekstrakcija pektina iz otpadne jabučne kaše primenom eutektičkih rastvarača na bazi holin hlorida

Pectin and pectin derived oligosaccharides can be obtained from waste apple pomace(biomass). Traditional method for pectin extraction involves use of diluted mineral acids atelevated temperatures, with yields of about 10 to 15%. As an alternative to conventionalmethods, the use of eutectic solvents is increasing because of their superior propertieswhen it comes to targeted extraction of certain components from biomass. The aim of thispaper is ultrasound assisted extraction of pectin from waste apple pomace using cholinechloride based eutectic solvents and lactic acid. Properties of extracted products wereexamined using FTIR spectroscopy and differential scanning calorimetry.Pektin i pektinski oligosaharidi mogu se dobiti iz otpadne jabučne kaše. Ovaj prirodni polimer ima široku primenu u industriji. Tradicionalna metoda za ekstrakciju pektina podrazumeva tretman razblaženim mineralnim kiselinama na povišenoj temperaturi, pri čemu se prinosi ostvaruju od oko 10 do 15%. Kao alternativa tradicionalnim rastvaračima sve češće se koriste i eutektički rastvarači, koje odlikuju daleko superiornija svojstva kada je reč o ciljanoj ekstrakciji određenih komponenti iz biomase. Cilj ovog rada je ultrazvučna ekstrakcija pektina primenom eutektičkih rastvarača na bazi holin hlorida i mlečne kiseline. Svojstva ekstrahovanog proizvoda ispitana su primenom FTIR spektroskopije i diferencijalne skenirajuće kalorimetrije

Structural characteristics of Ag nanoparticles synthesized in situ within pnipaam hydrogel by γ-irradiation

In this work, silver nanoparticles (AgNPs) are synthesized within thermo responsive poly(N-isopropylacrylamide) (PNiPAAm) hydrogels of different concentrations, by γ-irradiation. The UV-Vis plasmon absorption characterization of AgNPs and its modeling using Mie theory showed that their diameters are less than 20 nm. The X-ray diffraction (XRD) data are consistent with the face centered cubic (FCC) crystal structure of bulk metallic Ag. The negative lattice strain (lattice contraction) was observed for the samples where the AgNPs are incorporated in the xerogel solid matrix of highest polymer concentration (15 wt.% PNiPAAm). The lattice parameter values are found to be higher than the bulk lattice parameter of Ag for larger nanoparticles formed in 5 wt.% PNiPAAm, whereas the crystallites were under tensile stress. On the other hand, for smaller nanoparticles formed in 15 wt.% PNiPAAm, crystallites were under compression stress (negative stress) whereby the lattice is contracted

Hydrogels based on poly(methacrylic acid) for controlled release of anti-inflammatory drugs

Everyday struggle of humanity with novel diseases and present once, urge researchers to find novel and improve existing therapies to enhance their efficiency and safety. One of the promising approaches to overcome these challenges is controlled release of drugs. Biomaterials based on poly(methacrylic acid) (PMAA) are excellent drug delivery systems because they can control release rate and released amount of drug. Also, due to their pH sensitivity the PMAA hydrogels can release drug at the site of action. Namely, these nontoxic and biocompatible hydrogels swell in the environment with pH value higher than pKa of PMAA (4.6) and release encapsulated drug during the process. In present study, PMAA hydrogels are synthetized under ambient conditions by simple, cost effective and eco-friendly synthesis. Novel initiation system based on hydrogen peroxide, potato peel peroxidase and vitamin C (VC) is used for the first time for free radical polymerization of PMAA hydrogel. In accordance with the principles of circular economy, peroxidase was isolated from potato peel waste by water extraction for 12 h at 4 ℃. Four PMAA hydrogels were prepared by using potato peel peroxidase with various enzyme activity (0.4; 0.8; 1.2 and 1.8 IU), whereas the amounts of H2O2 (30 mL) and VC (10 mg) have been kept constant. The composition of the PMAA hydrogels was confirmed by FTIR analysis, whereas their porous structure was revealed by SEM. The swelling of the PMAA hydrogels was monitored in two media: 0.1M HCl (as simulation of human stomach) and phosphate buffer with pH 7.4 (as simulation of human intestines). In order to encapsulate anti-inflammatory drug – dexamethasone into the PMAA hydrogels, the hydrogels were immersed into the dexamethasone aqueous solution (5 mg/ml) and left to swell to the equilibrium, after which they were dried at room temperature. Dexamethasone release from the PMAA hydrogels was monitored in the same environments as was the PMAA swelling. The results showed that around seven times higher amount of dexamethasone was released in the medium with pH 7.4 than in the medium with pH 1. Present study has showed that the PMAA hydrogels, prepared through green and eco-friendly method, have huge potential for encapsulation and controlled release of anti-inflammatory drugs and therefore, for the treatment of rheumatoid arthritis

Copolymer hydrogels based on N-isopropylacrylamide and itaconic acid

In this study, the swelling behaviour of copolymer hydrogels of N-isopropylacrylamide (NIPAM) and itaconic acid (IA) in response to temperature and pH value of the external media was studied. The equilibrium degree of swelling for PNIPAM and PNIPAM/IA copolymers was greater at 25 degrees C than at 37 degrees C. The degree of swelling was low at low pH values. As the degree of ionization increased above the nominal pK(a) values of IA, the increased hydrophilicity resulted in larger degrees of swelling. At 37 degrees C, the PNIPAM hydrogel and some copolymers show anomalous swelling behaviour, i.e. the overshooting effect, in buffered solutions of certain pH values. A swelling-deswelling study showed that the deswelling process of the hydrogels was faster then the swelling process. According to dynamic swelling studies, the diffusion exponent and the diffusion coefficient both increase with increasing content of IA

Semi-interpenetrirajuće mreže hitozana i poli(etilen glikola)

Chitosan is a natural polycationic polymer that possesses useful properties such as bioactivity, biocompatibility, non-toxicity and non-antigenicity. On the other hand, its mechanical properties are not good for some biomedical application. They may be improved by preparing semi-interpenetrating polymer networks (semi-IPNs), when the hydrogel network is prepared in the presence of a previously made polymer such as poly(ethylene glycol). This paper deals with synthesis and characterization of the semi-interpenetrating polymer networks of chitosan and poly(ethylene glycol) with different Ch/PEG ratio and crosslinking degree. The degree of deacetylation of chitosan was determined by potentiometric titration, titration and elemental analysis. The semi-IPNs were characterized by swelling kinetics, mechanical properties and thermal analysis. It was found that PEG content and crosslinking agent concentration significantly influence the swelling behaviour of semi-IPNs. Water uptake was higher for lower crosslinking agent concentrations and PEG contents, up to PEG/Ch = 0,75. Better mechanical strength of semi-IPNs was obtained for higher PEG content and crosslinking agent concentration. SEM analysis confirmed the porous structure of semi-IPNs. Increasing the degree of crosslinking and PEG content up to PEG/Ch = 0,75, the pore size decreased. Based on the pore size, the investigated semi-IPNs can be regarded as macroporous. Thermogravimetric analysis showed that thermal stability of the semi-IPNs depends on the degree of crosslinking, as well as on the PEG content.Tema ovog rada je sinteza i karakterizacija semi-interpenetrirajućih polimernih mreža (semi-IPM) hitozana (Ch) i poli(etilen glikola) (PEG) sa različitim odnosom PEG/Ch i stepenom umreženja. Ispitana je kinetika bubrenja u rastvoru pH 2,2, mehanička svojstva, termička stabilnost i morfologija sintetisanih semi-IPM. Utvrđeno je da stepen umreženja i sadržaj PEG u semi-IPM utiču na bubrenje i termičku stabilnost semi- IPM. Dodatak PEG-a poboljšava mehanička svojstva za sve ispitane odnose PEG/Ch, pri čemu se stepen bubrenja semi-IPM nije mnogo promenio. Na taj način su dobijeni hidrogelovi koji dovoljno bubre i istovremeno imaju dobra mehanička svojstva, što ih čini pogodnim za primenu u medicini i farmaciji. SEM analiza je pokazala da sintetisane semi-IPM imaju poroznu strukturu. Na osnovu veličine pora, izračunate primenom teorije ravnotežnog bubrenja, ispitivane semi-IPM se mogu klasifikovati kao makroporozne

Swelling behaviour and paracetamol release from poly(N-isopropylacrylamide-itaconic acid) hydrogels

Copolymer hydrogels of N-isopropylacrylamide and itaconic acid (IA), crosslinked with N,N'-methylenebisacrylamide, were prepared by radical copolymerization. These hydrogels were investigated with regard to their composition to find materials with satisfactory swelling and drug release properties. A paracetamol is used as a model drug to investigate drug release profile of the hydrogels. It was found that the investigated hydrogels exhibited pH- and temperature-dependent swelling behaviour with restricted swelling and lower equilibrium degree of swelling at lower pH values and temperatures above the LCST value of PNIPAM (around 34 A degrees C). The diffusion exponent for paracetamol release indicate that the mechanism of paracetamol release are governed by Fickian diffusion, while in all release media initial diffusion coefficient was lower than late time diffusion coefficient. Furthermore, the paracetamol release rate depends on the hydrogel degree of swelling and it increased in the first stage of diffusion process, whereas was no significant difference thereafter. The presence of the IA moieties incorporated into the network weakened the shear resistance of the hydrogels. In order to calculate the pore size the characteristic ratio for PNIPAM, C (n) = 11.7, was calculated. Based on the pore size, the investigated hydrogels can be regarded as microporous. According to the obtained results swelling behaviour, mechanical properties, drug-loading capacity and the drug release rate could be controlled by hydrogel composition and crosslinking density, which is important for application of the investigated hydrogels as drug delivery systems