| Abstract | Globalni problem opterećenja okoliša čestičnim tvarima iz različitih izvora nametnuo je potrebu istraživanja njihova podrijetla, karakterizacije te prevencije generiranja. U skladu s navedenim u ovom istraživanju, koje je provedeno u četiri faze, praćen je utjecaj konvencionalnih i naprednih procesa predobrade poliesterske tkanine s ciljem poboljšanoga vezanja biopolimera kitozana i smanjenja sadržaja čestične tvari u efluentima od procesa pranja. Konvencionalni postupci alkalne hidrolize provedeni su uz dodatak promotora, a napredni procesi predobrade primjenom tehnologije niskotlačne hladne plazme i ozoniranja. Utjecaj konvencionalnih i naprednih procesa predobrade poliesterske tkanine na postizanje poboljšanoga vezanja biopolimera kitozana i smanjenja sadržaja čestične tvari u otpadnoj vodi nadziran je u prve tri faze istraživanja u kojima su promatrani fenomeni praćeni analizom: i) svojstava i stabilnosti dobivenih polimernih struktura poliester/kitozan; ii) svojstava i stabilnosti dobivenih polimernih struktura poliester/kitozan nakon procesa pranja; iii) efluenata od procesa pranja s naglaskom na sadržaj čestične tvari; iv) filtarskog kolača dobivenog membranskom filtracijom efluenata od procesa pranja. U četvrtoj fazi istraživanja svi dobiveni rezultati obuhvaćeni su u provedbi hijerarhijske klaster analize kako bi se definirale sveobuhvatne sličnosti i razlike među promatranim uzorcima prije i nakon predobrada, modifikacije kitozanom i procesa pranja. Primjenom normiranih i instrumentalnih metoda analize svojstava tekstilnog materijala istražen je utjecaj procesa pranja na postignuta funkcionalna svojstva. Karakterizacija neobrađene i predobrađene poliesterske tkanine te formirane strukture poliester/kitozan provedena je određivanjem debljine i vlačnih svojstava. Nadalje su korištene metode određivanja vrijednosti pH vodenog ekstrakta, apsorbirane vode, potencijal strujanja, identifikacije kitozana, infracrvena spektroskopija s Fourierovom transformacijom (FTIR). Određivane su i morfološka obilježja tkanine i dobivene strukture, sadržaj karboksilnih skupina te antimikrobna aktivnost. Nakon izlaganja polimerne strukture čimbenicima u procesu pranja sa standardnim deterdžentom istražen je njihov utjecaj na postignuta funkcionalna svojstva te na potencijal otpuštanja čestica koji je praćen karakterizacijom efluenata fizikalno-kemijskim metodama s naglaskom na određivanje čestične tvari. Za karakterizaciju efluenata od procesa pranja predobrađene poliesterske tkanine te formirane strukture poliester/kitozan upotrijebljene su metode određivanja ukupne suspendirane, ukupne otopljene i ukupne čvrste tvari, vrijednosti pH i elektrovodljivosti, mutnoće, određivanja kemijske potrošnje kisika te biokemijske potrošnje kisika, analiza veličina i raspodjele čestica te zeta potencijal i elektroforetska mobilnost čestica. Karakterizacija filtarskog kolača provedena je mikroskopijom uparenom s FTIR spektroskopijom. Rezultatima istraživanja potvrđeno je da predobrađena i aktivirana površina poliesterske tkanine pokazuje veći afinitet za modifikacije svojstava biopolimerom kitozanom čime je dobivena struktura poliester/kitozan. Dobivene strukture poliester/kitozan zadržale su stabilnost nakon provedenih ciklusa pranja. Povoljno zaštitno djelovanje kitozana u dobivenim strukturama potvrđeno je u svim ciklusima pranja, a posebice u početnim ciklusima koji se smatraju ključnima za znatan potencijal otpuštanja čestične tvari. Provedena hijerarhijska klaster analiza, na svim dobivenim rezultatima, pokazala se svrsishodnom metodom za definiranje sličnosti i razlika među dobivenim poliester/kitozan strukturama prije i nakon procesa pranja. |
| Abstract (english) | The global problem of environmental pollution by particulate matter from various sources has led to the need to investigate the origin, characterisation and prevention of the formation of particulate matter. In accordance with the statements of this study, which was carried out in four phases, the effects of conventional and advanced pretreatment processes of polyester fabrics were monitored with the aim of improving the binding of the biopolymer chitosan and reducing the particles in the effluents from the washing process. Conventional alkaline hydrolysis processes with the addition of promoters and advanced pretreatment processes using low pressure cold plasma and ozonation technology were carried out. The effects of the conventional and advanced pretreatment processes of polyester fabrics on achieving improved binding of the biopolymer chitosan and reducing particles in the wastewater were monitored in the first three research phases, in which the observed phenomena were analysed by: (i) properties and stability of the polyester/chitosan polymer structures; (ii) properties and stability of the obtained polyester/chitosan polymer structures after washing; (iii) effluents from washing, focusing on the content of particulate matter; (iv) filter cake obtained by membrane filtration of the washing effluents. In the fourth phase of the study, all the results obtained were included in the implementation of a hierarchical cluster analysis in order to define similarities and differences between the samples observed before and after pretreatment, modification with chitosan and washing. The influence of the washing process on the obtained functional properties was investigated by applying standardised and instrumental methods to analyse the properties of textile material. The characterisation of the untreated and pretreated polyester fabric and the polyester/chitosan structure formed was carried out by determining the thickness and tensile properties. In addition, the methods for determining the pH value of the aqueous extract, the absorbed water, the streaming potential, chitosan identification and Fourier transform infrared spectroscopy (FTIR) were used. The morphological properties of the fabric and the structures obtained, the content of carboxyl groups and the antimicrobial activity were also determined. The resulting polymer structure was subjected to a washing process with a standard detergent at 60°C for 10 cycles to investigate the influence of the washing process on the obtained functional properties. The effluents were collected after each washing cycle and combined into a composite sample, from the first to the fifth cycle, from the sixth to the tenth cycle and in total from the first to the tenth cycle. The wastewater from the washing process was analysed by determining the particle content with the task of identifying released fibre fragments and the influence of the processing procedures on the release potential. Methods for determining total suspended solids, total dissolved solids, total solids, pH and electrical conductivity, turbidity, determination of chemical oxygen demand and biochemical oxygen demand, analysis of particle size and distribution, zeta potential and electrophoretic mobility of the particles were used for characterization of effluents from the washing of the pretreated polyester fabric and the polyester/chitosan structure formed. In addition to the analysis of the wastewater, an analysis of the filter cake obtained by membrane filtration of the wastewater was carried out to detect the released fibrils.The characterisation of the filter cake was carried out by microscopy in conjunction with FTIR spectroscopy. The results of the investigation confirmed that the pretreated and activated surface of the polyester fabric has a greater affinity for the modification of properties by the biopolymer chitosan, resulting in a polyester/chitosan structure. The polyester/chitosan structures obtained retained their stability even after washing cycles. The favourable protective effect of chitosan in the obtained structures was confirmed in all washing cycles, especially in the first cycles, which are considered crucial for the significant potential of particle release. The advanced pretreatment of polyester fabrics with low-pressure cold plasma technology and ozonation can be used as a technologically acceptable and more environmentally friendly substitute for conventional processes. Pretreatment processes and the number of washing cycles influence the content of particulate matter originally belonging to the biopolymer or polymer component of the polyester/chitosan structure. The characterisation of wash effluents by adjusting the TSS/TDS ratio and determining the characteristic particle diameters from the size distribution function enables the detection of the size categorisation of potentially released particles in the washing process. Particle size distribution is a useful method for the characterisation of effluents from the washing of polyester/chitosan structures as it enables the establishment of relationships with other parameters used for the characterisation of effluents. The distribution of size particles in effluents from the washing of polyester/chitosan structures depends on the structure of the polymer, the interaction of chitosan with the structure, the stability of the modification through successive washing cycles, the content and size of suspended particles and the effect of factors in the washing process. Colloids and particles, which are responsible for the degree of turbidity, usually have a negative surface charge, which is expressed by the zeta potential of the particles in the solution. Together with the electrophoretic mobility of the particles, they represent a valuable parameter in the characterisation of effluent particles. The application of micro-FTIR spectroscopy in analysing the filter cake obtained by membrane filtration of the effluent proved to be an effective method for detecting released particles and/or microfibrils. Hierarchical cluster analysis as an advanced statistical technique has proven its usefulness in analysing similarities and differences between polyester/chitosan structures prepared by different pretreatments and washing cycles. |
