Učinkovitost celuloznih membran kot adsorbentov kationskih barvil

magistrsko delo

Laura Maleš (Author), Darinka Fakin (Mentor), Selestina Gorgieva (Co-mentor)

Abstract

S problematiko obarvanih odpadnih voda se srečujejo v vseh tekstilnih industrijah. Z željo po ponovni uporabi barvil, čim manjšim onesnaženjem ter večji učinkovitosti barvanja se razvijajo tehnologije, ki bi odpadno vodo na najučinkovitejši in cenovno ugoden način pred izpustom v vodotok tudi prečistile. Predhodne raziskave so pokazale, da je ena izmed bolj učinkovitih fizikalnih metod ločevanja barvil membranska adsorpcija. V raziskovalnem delu smo preučevali možnosti in načine s katerimi uspešno ločiti kationska barvila z uporabo membranskih adsorbentov na osnovi celuloze. Za ta namen smo izdelali dve vrsti membran na osnovi celuloze: prvo smo sintetizirali s pomočjo celuloznih nanofibrilov in karboksimetilirane celuloze, drugo pa smo pripravili z uporabo komercialne bakterjiske celuloze. V eksperimentalnem načrtu smo vključili tudi dodatno modifikacijo, torej oksidacijo bakterijske celuloze ter variacije med razmerji celuloznih nanofibrilov in karboksimetilirane celuloze z namenom da bi preučili vpliv prisotnosti različnih funkcionalnih skupin na funkcionalnost membran. Uporabljeni kationski barvili sta antrakinonsko barvilo C.I. Basic Blue 47 in azo barvilo C.I. Basic Yellow 29. Metode s katerimi smo analizirali fizikalno kemijske in morfološke lastnosti membran so atenuirana popolna refleksija infrardeče spektroskopije s Fourierjevo transformacijo (ATR – FTIR) , goniometrija, potenciometrična titracija ter konfokalna optična mikroskopija. UV – VIS spektroskopijo smo uporabili pri preučevanju efikasnosti adsorpcije ter hitrost (kinetika) adsorpcije dveh kationskih barvil na posameznih membranah. Pri ATR – FTIR spektrih membran smo lahko identificirali prisotnost celuloze 3340 cm-1, tvorbo novih vezi navezujoč se na aldehidne skupine pri oksidaciji bakterijske membrane 1700 cm-1 in 890 cm-1, prisotnost karboksimetiliranih eterskih skupin okrog 1020 cm-1, raztezanje OH skupin okrog 1318 cm-1 ter raztezanje C-H vezi pri CH2 in CH3 skupinah pri 2898 cm-1. Glede na vrednosti skupnega negativnega naboja merjenega pri potenciometrični titraciji, pričakujemo največje adsorpcijske sposobnosti za 4CMC4CNF+CA (Q/m = 1,0675 mmol/g) ter najmanjše za BCoxd (Q/m = 0,2094 mmol/g). Membrane, ki so bolj negativno nabite bodo pozitivno nabito barvilo posledično boljše adsorbirale. Poleg naboja membrane je pomemben dejavnik za adsorpcijo barvila tudi struktura membrane, ki je razvidna iz mikrografov. Rezultati posnetkov konfokalne optične mikroskopije so pokazali, da so izmed vseh najbolj vlaknaste 4CMC4CNF+CA membrane, iz česa lahko sklepamo, da bodo imele tudi največji potencial adsorpcije zaradi večje aktivne površine. Ob zaključku eksperimentalnega dela, smo ugotovili, da se je obarvana raztopina skoraj povsem razbarvala, kar pomeni, da je bila ločitev kationskega barvila iz vodnega medija uspešna. Membrane na osnovi CMC/CNF so antrakinonsko barvilo 100% učinkovito odstranile, medtem ko je BC le – to barvilo 24,3% učinkovito odstranila in BCoxd 23,6%. Razlika pri membranah na osnovi BC je bila minimalna. Azo barvilo so membrane adsorbirale nekoliko slabše in sicer okrog 7-9% membrane na osnovi CMC/CNF ter 5,57% BC in 7,33% BCoxd membrana. Za najbolj učinkovite so se v obeh primerih pokazale membrane na osnovi 4CMC4CNF+CA. Po vseh opravljenih analizah lahko zaključimo, da so najbolj učinkovit adsorbent izbranih kationskih barvil 4CMC4CNF+CA membrane, sledijo 1CMC7CNF+CA, BCoxd in BC.

Keywords

celulozna membrana;membranska adsorpcija;kationska barvila;karboksimetilirana celuloza;celulozni nanofibrili;bakterijska celuloza;magistrske naloge;

Data

Language:	Slovenian
Year of publishing:	2019
Typology:	2.09 - Master's Thesis
Organization:	UM FS - Faculty of Mechanical Engineering
Publisher:	[L. Maleš]
UDC:	544.725:628.316.12(043.2)
COBISS:	23074326
Views:	833
Downloads:	125
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Efficiency of cellulose membranes as adsorbers of cationic dyes
Secondary abstract:	Colored wastewater is a problem in all textile industries. With the desire to reuse dyes, minimize contamination and increase the efficiency of dyeing, technologies are being developed that would purify wastewater in the most efficient and cost-effective way before being discharged into a watercourse. Previous research has shown that membrane adsorption is one of the more effective physical methods of separating dyes. In the research part, we investigated the possibilities and ways by which cationic dyes can be successfully separated using cellulose-based membrane adsorbents. For this purpose, two types of cellulose-based membranes were manufactured: the first was synthesized using cellulosic nanofibrils and carboxymethylated cellulose, and the second was prepared using commercial bacterial cellulose. An additional modification was included in the experimental design, ie oxidation of bacterial cellulose and variations between the ratios of cellulose nanofibrils and carboxymethylated cellulose in order to study the effect of the presence of different functional groups on the functionality of membranes. The cationic dyes used are C.I. Basic Blue anthracnone dye 47 and C.I. Basic Yellow azo dye 29. The methods used to analyze the physicochemical and morphological properties of the membranes are attenuated full reflectance infrared spectroscopy with Fourier transform (ATR - FTIR), goniometry, potentiometric titration and confocal optical microscopy. UV - VIS spectroscopy was used to study the adsorption efficiency and the adsorption rate (kinetics) of two cationic dyes on individual membranes. In the ATR - FTIR spectra of membranes, the presence of cellulose 3340 cm-1 could be identified, the formation of new bonds attaching to aldehyde groups upon oxidation of the bacterial membrane of 1700 cm-1 and 890 cm-1, the presence of carboxymethylated ether groups around 1020 cm-1, the elongation of OH groups of about 1318 cm-1 and the stretching of the CH bonds at the CH2 and CH3 groups at 2898 cm-1. Considering the values of total negative charge measured by potentiometric titration, we expect the highest adsorption capacity for 4CMC4CNF + CA (Q / m = 1.0675 mmol / g) and the lowest for BCoxd (Q / m = 0.2094 mmol / g). Membranes that are more negatively charged will, as a result, have a more positively charged dye adsorbed. In addition to the membrane charge, an important factor for dye adsorption is the structure of the membrane, which is evident from micrographs. The results of the confocal optical microscopy images revealed that they are the most fibrous 4CMC4CNF + CA membranes, which can be concluded to have the highest adsorption potential due to the larger active surface. At the conclusion of the experimental work, we found that the colored solution was almost completely discolored, which means that the separation of the cationic dye from the aqueous medium was successful. CMC / CNF based membranes were 100% efficiently removed by the anthraquinone dye, while 24.3% were effectively removed by BC and 23.6% by BCoxd. The difference in BC-based membranes was minimal. Azo dye adsorbed the membranes slightly worse, with about 7-9% CMC / CNF based membranes and 5.57% BC and 7.33% BCoxd membranes. The membranes based on 4CMC4CNF + CA were shown to be the most effective in both cases. After all the analyzes performed, we can conclude that the most effective adsorbent of the selected cationic dyes is 4CMC4CNF + CA membranes, followed by 1CMC7CNF + CA, BCoxd and BC.
Secondary keywords:	cellulose membrane;membrane adsorption;cationic dyes;carboxymethylated cellulose;cellulose nanofibrils;bacterial cellulose;
Type (COBISS):	Master's thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za strojništvo, Tehniško varstvo okolja
Pages:	XVII, 67 str.
ID:	11283734