Modifikacija komercijalnih nanofiltracijskih membrana radi poboljšanja njihovih performansi

master's thesis

• Title (english): Modification of commercial nanofiltration membranes to improve their performances
• Author: Alegra Vezjak Fluksi
• Mentor: Krešimir Košutić (mentor)
• Committee member: Krešimir Košutić (predsjednik povjerenstva)
• Committee member: Sandra Babić (član povjerenstva)
• Committee member: Aleksandra Sander (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2024-07-11, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Tlačni membranski proces nanofiltracije (NF) koristi se za obradu vode za piće i otpadnih voda. Kako obično ne pokazuju visoke faktore separacije prema nenabijenim molekulama male molekulske mase, cilj ovog istraživanja bio je poboljšati učinkovitost triju komercijalnih NF membrana (NF90, TS80, DK) pri uklanjanju N-nitrozodimetilamina (NDMA) modifikacijom pomoću 4-nitrobenzensulfonil klorida (NBS) kao molekulskog blokatora. Analiziran je sastav struja prije i nakon nanofiltracijske obrade te je praćena permeabilnost vode, odnosno protok permeata. Također su ispitane i promjene površine membrana, tj. njihov aktivni sloj nakon postupka modifikacije. Rezultati pokazuju da je modifikacijom komercijalne DK membrane NBS-om povećan faktor separacije NDMA molekule s 26,0 % na 45,2 % uz zadržavanje
75,93 % početne permeabilnosti čiste vode, što je daleko bolje od preostalih membrana čija se permeabilnost smanjila za 54,84 i 61,29 %. NF90 membrana pokazuje povećanje faktora separacije NDMA molekule s 20,9 na 47,1 %, što je 4,03 % bolje od DK membrane te pokazuje i najviši faktor separacije soli. Ni jedna od ispitivanih membrana nije pokazala dovoljno visok faktor separacije NDMA molekule da bi zadovoljila regulativama zadane granice koncentracija u vodi za piće.

Abstract (english)

Pressure-driven nanofiltration (NF) processes are used in drinking water and wastewater treatment. Since they often don't show high rejection rates of uncharged particles of low molecular weight, the goal of this research was to enhance the N-nitrosodimethylamine (NDMA) rejection efficiency for three commercially available NF membranes (NF90, TS80, DK) via modification using 4-nitrobenzenesulfonyl chloride (NBS) as a molecular plug. Stream compositions were analysed after and prior to the nanofiltration treatment. Water permeability, or rather permeate flow, was measured and changes in the membrane surface, i.e. their active layers post modification were analysed as well. Results show that modifying the commercially available DK membrane increased the rejection rate of NDMA molecule from 20,0 % to 45,2 % while retaining 75,93 % of its original pure water permeability which is miles above the other membranes whose permeability dropped by 54,84 and 61,29 %. The NF90 membrane shows an increase of NDMA molecule rejection rates from 20,9 % to 47,1 % which is 4,03 % higher than the DK membrane, as well as showing the best salt rejection rates. None of the membranes tested here reached NDMA molecule rejection rates high enough to meet the allowed concentrations in drinking water set by regulatory bodies.

• Keywords: nanofiltracija; modifikacija; faktor separacije; permeabilnost vode
• Keywords (english): nanofiltration; modification; rejection rate; water permeability
• Language: croatian
• URN:NBN: urn:nbn:hr:149:065399
• Study programme: Title: Chemical Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-09-01
• Created on: 2024-07-15 13:27:06