Učinkovitost nanofiltracije pri odstranjevanju kovinskih ionov iz modelne vode

diplomska naloga

Aleksandra Španbauer (Author), Aleksandra Lobnik (Mentor), Maja Bauman (Co-mentor)

Abstract

Ioni določenih kovin v vodi lahko že v nizkih koncentracijah škodujejo zdravju in obremenjujejo okolje in žive organizme. Med učinkovitejše sisteme odstranjevanja kovinskih ionov iz vode sodijo membranske filtracije, kot npr. nanofiltracija (NF). NF membrane imajo večinoma sposobnost zadrževanja večvaletnih kationov, med njimi tudi ionov težkih kovin, monovalentne ione pa glede na filtracijske zakonitosti prepuščajo. Eksperimentalni del diplomskega dela zajema karakterizacijo dveh nanofiltracijskih membran ter v nadaljevanju študij zadrževanja ionov težkih kovin, prisotnih v modelni vodi. Izbrane soli težkih kovin (so sestavljene iz kationov različnih molekulskih mas in velikosti ter z nitratnega aniona (NO3-)). Filtracija modelne vode je potekala skozi izbrani in karakterizirani NF membrani, pri različnih delovnih pogojih (pH 4; 7; 9 in tlaku 5; 10; 15; 20 bar). V rezultatih je podana učinkovitost filtracije kot retencija, ločeno za ione težkih kovin in nitratne anione pri različnih izbranih delovnih pogojih. Rezultati eksperimentalnega dela so uvodoma pokazali, da je filtracijo modelne vode, ki vsebuje ione težkih soli smiselno izvajati le v kislem mediju (pH 4). Iz tehnološkega vidika je proces najbolj optimalno potekal pri najvišjem tlaku (20 bar), kjer je membrana v največji meri zadržala Zn2+ ione (90,3%), ki jim sledijo Pb2+ (79,1%) in Cd2+ (28,6%). Retencija nitratnih ionov je prav tako odvisna od prisotnega kationa in sledi trendu kovinskih ionov. Posebno pozornost je potrebno posvetiti čiščenju membrane in se pri tem izogniti tvorbi netopnih kovinskih hidroksidov v alkalnem mediju, ki membrano nepovratno zamašijo in poškodujejo.

Keywords

nanofiltracija;tankoslojne kompozitne membrane;karakterizacija membrane;ioni težkih kovin;modelna voda;učinek zadrževanja;membranska filtracija;čiščenje vode;ostranjevanje kovinskih ionov;

Data

Language:	Slovenian
Year of publishing:	2010
Source:	Maribor
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FS - Faculty of Mechanical Engineering
Publisher:	[A. Španbauer]
UDC:	628.353(043.2)
COBISS:	14171926
Views:	3388
Downloads:	332
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Efficiency of nanofiltration process by metal ion removal from model water
Secondary abstract:	Heavy metal ions in water can harm health and load the environment and living organisms, already when they are present in low concentrations. Among many conventional treatment methods, membrane separation processes, i.e. nanofiltration (NF) enables efficient heavy metal ion removal from wastewaters. Nanofiltration membranes should be able to reject multivalent cations, (including heavy metal ions), while the monovalent ions pass through the membrane. The experimental part of the diploma work includes the characterization of nanofiltration membranes and the study of heavy metal ion rejection. The selected heavy metal salts (Zn2+, Cd2+, Pb2+) are composed of various cations and nitrate anion (NO3-), thus having different molecular weight and size. Model water filtration was performed using two preliminary characterized nanofiltration membranes under different operating conditions (pH 4; 7; 9 and pressure 5; 10; 15; 20 bar). As the result the rejection efficiencies separately for heavy metal ions and nitrate anion are given considering different defined working conditions. On the basis of results we can state that the filtration process could be efficiently performed in acid media (pH 4). From technological point of view the process was optimally managed at the highest tested pressure (20 bar), where the retention efficiency was highest of Zn2+ ions (90.3%), followed by Pb2+ (79.1%) and Cd2+ (28.6%). Retention efficiency of nitrate ions depends on the kind of present cations and follows the trend of metal ions’ retention. Special attention has to be paid to the membrane cleaning in order to avoid the formation of insoluble metal hydroxides in alkali media, which irreversibly clog and damage the membrane.
Secondary keywords:	nanofiltration;thin film composite membranes;membrane characterization;heavy metal ions;model wastewater;retention efficiency;
URN:	URN:SI:UM:
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Mariboru, Fak. za strojništvo, Tekstilstvo
Pages:	XII, 99 f.
Keywords (UDC):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;engineering;technology in general;inženirstvo;tehnologija na splošno;public health engineering;water;sanitation;illuminating engineering;sanitarna tehnika;zdravstvena tehnika;voda;sanitarne naprave;svetlobna tehnika;sewage;treatment;disposal;utilization of sewage;odpadne vode;
ID:	1011317