Doprinos ispitivanju efikasnosti neoksidativnih inovativnih hibridnih procesa za uklanjanje ibuprofena, kofeina, diklofenaka i odabranih neorganskih mikropolutanata iz vode

Abstract

Ciljevi doktorske disertacije obuhvatili su: -Određivanje efikasnosti neoksidativnih hibridnih procesa za uklanjanje ibuprofena, kofeina, diklofenaka i odabranih neorganskih mikropolutanata jona arsena, hroma, bakra i cinka iz realnog matriksa otpadne vode, i -Dobijanje novog znanja o uticaju različite strukture rastvorene organske materije i fizičko-hemijskih osobina ibuprofena, kofeina i diklofenaka na efikasnost uklanjanja. U tu svrhu primenjeni su različiti inovativni neoksidativni hibridni procesi: -Hibridni membranski procesi u kombinaciji sa aktivnim ugljem u prahu (PAC doza 5 mg/L) zasebno i u kombinaciji sa gvožđe(III)- hloridom (FeCl3) (doza 4,0 mg Fe (III)/L) ili prirodnim koagulantom izolovanim iz semena pasulja (doza 33µl/L) za uklanjanje ibuprofena, kofeina i diklofenaka pri početnim koncentracijama 2-3 µg/L i arsena, hroma, bakra i cinka pri početnim koncentracijama oko 100 µg/L iz efluenta postrojenja za prečišćavanje komunalne otpadne vode (PPOV). Pre testiranja hibridnih membranskih procesa, ispitana je ultrafiltracija (UF) zasebno kako bi se procenila sorpcija odabranih polutanata na UF membrani. U primenjenim membranskim i hibridnim membranskim procesima efikasnost uklanjanja ibuprofena, kofeina i diklofenaka varira od toga da se uopšte ne dešava do 68%, 87%, 87% i 50%, redom. Najbolje se uklanja kofein i to u procesu kada se adsorpcija na aktivnom uglju kombinuje sa koagulantom na bazi gvožđa (42-87%). Prirodni koagulant u hibridnom procesu je pokazao uglavnom loš učinak. U pogledu jona arsena i odabranih metala hibridni membranski procesi su se pokazali kao najefikasniji u slučaju jona cinka (postignuta efikasnost 44-50% za PAC/UF proces, 78-87% za PAC/FeCl3/UF i 59-71% za PAC/prirodni koagulant/UF proces) i jona hroma (postignuta efikasnost 33-75% za PAC/UF proces, 41-87% za PAC/FeCl3/UF proces i 58-76 za PAC/prirodni koagulant/UF proces). Pomenuti procesi su bili najmanje efikasni u slučaju jona arsena (maksimalna efikasnot 13-19% za PAC/FeCl3/UF proces). -Hibridni procesi u kojima se koristi prirodni koagulant izolovan iz semena pasulja (doza 37,5 µl/L), zasebno i u kombinaciji sa kaolinitom (doza 100 mg/L) za uklanjanje arsena i pomenutih metala. Koagulaciona aktivnost prirodnog koagulanta potvrđena je za uklanjanje jona cinka (postignuta efikasnost 23–52%) i jona arsena (postignuta efikasnost 32–39%) iz efluenta PPOV. Kaolinit je bio efikasan samo u slučaju jona arsena (efikasnost uklanjanja 36–48%). Hibridni proces koagulacija/adsorpcija nije pokazao nikakav efekat u poređenju sa zasebnim procesima. -Hibridni proces u kom se koriste PAC i prirodni koagulant za uklanjanje ibuprofena, kofeina i diklofenaka (c0=2-3 µg/L, doza uglja 5 mg/L, doza koagulanta 37,5 µl/L) u sintetičkim matriksima sa i bez jedinjenja koja su bila surogati rastvorenog organskog ugljenika (DOC) malih i velikih molekulskih masa i u efluentu PPOV. Pri istim uslovima testiran je i PAC zasebno. Ispitivanje učinka PAC sa i bez prisustva prirodnog koagulanta (vreme kontakta uglja 30 minuta) pokazalo je različito ponašanje uklanjanja organskih mikropolutanata (OMP) u zavisnosti od vrste organske materije u ispitivanim matriksima. Dodatak prirodnog koagulanta imao je pozitivan uticaj na efikasnost uklanjanja ibuprofena u sintetičkom matriksu bez dodatka surogata organske materije 25-45% i oko 10% u sintetičkom matriksu sa dodatkom surogata velikih molekulskih masa. Pozitivan efekat je uočen u slučaju kofeina u matriksu sa dodatkom surogata velikih molekulskih masa 10-15% i u efluentu PPOV 12%. Negativan uticaj prirodnog koagulanta u svim matriksima uočen je kod diklofenaka koji je manje hidrofilan u odnosu na ibuprofen i kofein iako nosi negativno naelektrisanje slično ibuprofenu. U ostalim navedenim matriksima nije bilo uticaja. a osnovu testova adsorpcione kinetike utvrđeno je da se ravnoteža najbrže uspostavlja u sintetičkom matriksu sa i bez dodatka surogata DOC malih molekulskih masa za sve tri ispitivane supstance (posle 2 h). Dodatak surogata velikih molekulskih masa produžava vreme neophodno za uspostavljanje ravnoteže u slučaju sve tri ispitivane supstance na 24-48 h. U kompleksnom matriksu sa dodatkom smeše surogata velikih i malih molekulskih masa ravnoteža se uspostavlja u roku od 2-24 h, dok je u efluentu PPOV ona postignuta za 24 h. Tokom eksperimenata primećena je desorpcija, uglavnom u matriksima sa dodatkom surogata velikih molekulskih masa i u efluentu. Aproksimacija brzine transporta OMP kroz film ukazuje da mali molekuli DOC ubrzavaju transport ibuprofena, kofeina i diklofenaka u odnosu na sintetički matriks. To je najizraženije kod kofeina. U prisustvu surogata velikih molekulskih masa i u efluentu obe negativno naelektrisane supstance imaju niži koeficijent transfera mase kroz film, dok su kod kofeina prisutni umanjeni, ali ipak pozitivni efekti u odnosu na sintetički matriks. Utvrđeno je da različita struktura rastvorene organske materije utiče na adsorpcionu kinetiku OMP, dok na krajnju efikasnost u ravnotežnim uslovima ne (postignuta efikasnost u svim matriksima za ibuprofen, kofein i diklofenak >80%, osim u slučaju diklofenaka kod kog je u efluentu PPOV uočena efikasnost od 28% i 34% za period mešanja od 24 h i 48 h, redom).

The aims of the research were: -Determining the efficiency of non-oxidative hybrid processes for the removal of ibuprofen, caffeine, diclofenac and selected inorganic micropollutants of arsenic, chromium, copper and zinc from municipal wastewater treatment plant effluent, and -Obtaining new knowledge about the influence of the different kind of dissolved organic matter (high and low molecular mass) and the physicochemical properties of ibuprofen, caffeine and diclofenac on the removal efficacies. For this purpose, various innovative non-oxidative hybrid processes have been tested: -Hybrid membrane processes in combination with powdered activated carbon (PAC, dose 5 mg/L) separately and with ferric chloride (FeCl3, dose 4.0 mg Fe (III)/L) or a natural coagulant isolated from bean seeds (dose 33 µl/L) for the removal of ibuprofen, caffeine and diclofenac (c0=2-3 µg/L) and for the removal of arsenic, chromium, copper and zinc (c0=100 µg/L) from municipal wastewater treatment plant effluent (WWTP effluent ). Before testing the hybrid membrane processes, ultrafiltration (UF) was performed separately to evaluate the sorption of selected pollutants on the UF membrane. During the applied membrane and hybrid membrane processes, the removal efficiency of ibuprofen, caffeine, and diclofenac fluctuated from none to 68%, 87%, 87%, and 50%, respectively. Caffeine was best removed with the PAC/FeCl3/UF process (42-87%). The natural coagulant in the hybrid process showed mostly poor performance. In terms of arsenic and the selected metals, hybrid membrane processes proved to be the most effective in the case of the zinc (achieved effects are 44-50% for the PAC/UF process, 78-87% for PAC/FeCl3/UF and 59-71% for PAC/natural coagulant/UF process) and chromium (achieved efficiency are 33-75% for PAC/UF process, 41-87% for PAC/FeCl3/UF process and 58-76 for PAC/natural coagulant/UF process). These processes were the least efficient in the case of arsenic (only 13-19% for the PAC/FeCl3/UF process). -Hybrid processes using a natural coagulant isolated from bean seeds (dose 37.5 µl/L), separately and in combination with kaolinite (dose 100 mg/L) to remove arsenic and the metals. The coagulation activity of the natural coagulant was confirmed for the removal of zinc (23–52%) and arsenic (32– 39%) from WWTP effluent. Kaolinite was effective only in the case of arsenic (removal efficiency 36–48%). The hybrid coagulation/adsorption process did not show any effect compared to the separate processes. -Hybrid process PAC/natural coagulant was tested to remove ibuprofen, caffeine and diclofenac (c0=2-3 µg/L, PAC dose 5 mg/L, coagulant dose 37,5 µg/L) in synthetic matrices with and without a dissolved organic carbon (DOC) surrogate (high and low molecular mass) and WWTP effluent. Under the same conditions, PAC was tested separately. Examination of the performance of PAC with and without the presence of natural coagulant (PAC contact time 30 minutes) showed different organic micropollutants (OMP) removal behavior depending on the kind of organic matter. The addition of natural coagulant had a positive effect on the efficiency of ibuprofen removal in the synthetic matrix without organic matter surrogates by 25-45% and about 10% in the synthetic matrix with the high molecular mass surrogates. A positive effect was observed in the case of caffeine in the matrix with the high molecular mass surrogates 10-15% and in WWTP effluent 12%. The natural coagulant had a negative influence on the removal of diclofenac, which is less hydrophilic compared to ibuprofen and caffeine, although it carries a negative charge, similar to ibuprofen. There was no impact in the other tested matrices. Adsorption kinetics tests showed that equilibrium was most quickly reached in the synthetic matrix with and without the addition of low molecular mass surrogates for all three tested substances (after 2h). The addition of surrogates of high molecular mass increases the time necessary for the establishment of equilibrium in the case of all three tested substances to 24-48 h. In the complex matrix with the addition of a mixture of surrogates of high and low molecular mass, equilibrium was established within 2-24 h , while in the WWTP effluent it was achieved in 24 h. Desorption was observed in matrices with the addition of high molecular mass surrogates and in the WWTP effluent. An analysis of the OMP mass transfer through the film indicates that low DOC molecules accelerate the transport of ibuprofen, caffeine and diclofenac compared to the synthetic matrix. This is most pronounced with caffeine. In the presence of large mass surrogates and in the effluent, both negatively charged substances have a lower coefficient of mass transfer through the film, while with caffeine, they are reduced, but still have a positive effect compared to the synthetic matrix. It was shown that the different kind of dissolved organic matter affects the adsorption kinetics of OMP, while the final efficiency in equilibrium conditions was not affected (efficiency for all three substances in the examined matrices was >80%, except in the case of diclofenac, where removal of 28% and 34% were observed in the WWTP effluent for contact times of 24 and 48 h, respectively).