| 1. |
- Badea, Silviu-Laurentiu, et al.
(författare)
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Leachability and desorption of PCBs from soil and their dependency on pH and dissolved organic matter
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 499, s. 220-227
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Tidskriftsartikel (refereegranskat)abstract
- pH affects both soil–water partitioning coefficient (Kd) of polychlorinated biphenyls (PCBs) and dissolved organic matter (DOM), thereby influencing PCBs' leachability from contaminated soils. To explore these incompletely understood interactions, the leachability of 11 selected PCBs in a naturally aged soil was investigated in pH static leaching tests spanning a wide pH range (2 to 9). The Kd was calculated for each of the PCBs, based on their observed concentrations in the soil and leachates obtained from each test. The concentration and composition of DOM in each leachate were also determined, the latter using FTIR spectroscopy. Correlations between the DOM's FTIR spectra and Kd values were investigated by orthogonal projections to latent structures. The log Kd-values varied among the PCB congeners and were most variable at low pH, but the values for all studied congeners decreased with increasing pH, by up to 3 log units (for PCB 187). In the pH 5–7 interval, an abrupt decrease in log Kd values with increases in pH was observed, although the total organic carbon content remained relatively stable. The FTIR data indicate that fulvic and humic acids in DOM partially deprotonate as the pH rises from 5 to 7.
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| 2. |
- Badea, Silviu-Laurentiu, et al.
(författare)
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Leachability of PCBs in soil and its pH and dissolved organic matter (DOM) dependency
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The leachability of eleven selected PCBs from naturally aged soil (Västervik, Sweden) was investigated in relation to the composition and concentration of dissolved organic matter at different pH (2 to 9), using a pH static test with initial acid/base addition. The batch leaching tests were performed on 50 g aliquots of a PCBs contaminated soil at a liquid to solid ratio (L/S) of 10 L/Kg. The PCBs were analyzed by gas chromatography coupled with high resolution mass spectrometry (GC-HRMS). The composition and of dissolved organic matter (DOM) at different pH values was explored by FTIR spectroscopy. The correlation between the FTIR data obtained for DOM and the log Kd values of PCBs was explored by orthogonal projections to latent structures (OPLS). The log Kd-values of all target PCBs decreased with increased pH values and the log Kd-values were highly correlated with the concentration of total organic carbon (TOC) in the leachates. For the lower chlorinated congener, PCB 28, this correlation was weaker. The variation of fractions of concentrations of mono-ortho to di-ortho PCBs (PCB 66 to PCB 52 and PCB 105 to PCB 101) indicated an influence of the ortho-chlorine atoms through pH effects on their leachability. The FTIR analysis of DOM showed that the least chlorinated and hydrophobic PCB congeners (i.e. PCB 28) might be associated with the hydrophilic fraction (i.e. carboxylic groups) of the DOM.
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| 3. |
- Mustafa, Majid, et al.
(författare)
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Identification of resistant pharmaceuticals in ozonation using QSAR modeling and their fate in electro-peroxone process
- 2021
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Ingår i: Frontiers of Environmental Science and Engineering. - : Higher Education Press. - 2095-2201 .- 2095-221X.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The abatements of 89 pharmaceuticals in secondary effluent by ozonation and the electro-peroxone (Eperoxone) process were investigated. Based on the results, a quantitative structure-activity relationship(QSAR) model was developed to explore relationship between chemical structure of pharmaceuticalsand their oxidation rates by ozone. The orthogonal projection to latent structure (OPLS) method wasused to identify relevant chemical descriptors of the pharmaceuticals, from large number ofdescriptors, for model development. The resulting QSAR model, based on 44 molecular descriptorsrelated to the ozone reactivity of the pharmaceuticals, showed high goodness of fit (R2 = 0.963) andpredictive power (Q2 = 0.84). After validation, the model was used to predict second-order rateconstants of 491 pharmaceuticals of special concern (kO3 ) including the 89 studied experimentally. The predicted kO3 values and experimentally determined pseudo-first order rate constants of thepharmaceuticals’ abatement during ozonation (kOZ) and the E-peroxone process (kEP) were then usedto assess effects of switching from ozonation to the E-peroxone process on removal of thesepharmaceuticals. The results indicate that the E-peroxone process could accelerate the abatement ofpharmaceuticals with relatively low ozone reactivity (kO3 < ~102 M–1.s–1) than ozonation (3–10 min versus 5–20 min). The validated QSAR model predicted 66 pharmaceuticals to be highly O3-resistant.The developed QSAR model may be used to estimate the ozone reactivity of pharmaceuticals ofdiverse chemistry and thus predict their fate in ozone-based processes.
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| 4. |
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| 5. |
- Mustafa, Majid, et al.
(författare)
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Regeneration of saturated activated carbon by electro-peroxone and ozonation: Fate of micropollutants and their transformation products
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 776
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Tidskriftsartikel (refereegranskat)abstract
- Many micropollutants (MPs) that may adversely affect aquatic life when released into the environment are common in modern societies. The presence of MPs in the environment is frequently connected to release from wastewater treatment plants. Therefore, advanced treatments are needed to remove these MPs. Powdered activated carbon (PAC) efficiently removes MPs in both laboratory experiments and full-scale applications. However, its single-use nature and the difficulty of handling spent PAC have limited the popularity of this approach. Therefore, various methods for PAC regeneration have been investigated. The current study compares two methods for regenerating spent PAC saturated with MPs: ozonation and the electro-peroxone (E-peroxone) process. Six MPs were tested: benzotriazole, carbamazepine, ciprofloxacin, diclofenac, perfluorooctanoic acid (PFOA), and trimethoprim. Both methods achieved regeneration efficiencies (REs) of >100% for four of the MPs. However, the REs for diclofenac (95–102%) and PFOA (67–69%) were below 100%. Surface characterization showed that PAC regeneration did not restore the micro- and mesopores that are mainly responsible for MPs sorption by virgin PAC. Instead, MPs sorption onto regenerated PAC was determined to be related to different interactions between PAC surface and MPs' ionic states including electrostatic, H-bonding, and electron donor-acceptor interactions. Transformation products of adsorbed MPs typically remained sorbed on the regenerated PAC rather than being transferred to the regeneration effluent.
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| 6. |
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| 7. |
- Mustafa, Majid, 1987-
(författare)
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Removal of Micropollutants from Wastewater : evaluation of effect of upgrading ozonation to electro-peroxone
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The United Nations (UN) has adopted 17 “Sustainable Development Goals” (SDGs) to achieve a clean, better and sustainable future. SDG 6 is to ensure that everyone has access to clean water and sanitation by 2030. According to the UN Educational, Scientific and Cultural Organization (UNESCO), more than 80% of wastewater produced from human actions is discharged into rivers or seas without any pollution removal. Thus, the presence of micropollutants (MPs: including, inter alia, pharmaceuticals, biocides and personal care products) in wastewaters is a major challenge that poses potential threats not only to aquatic system but also to humans due to their potential toxicity and potential to induce antibiotic resistance. Wastewater treatment plants (WWTPs) are considered hotspots for release of MPs as the current treatment processes are not designed to remove them. This thesis is based on studies described in four appended papers (Papers I-IV) designed to help efforts to solve these problems by investigating the factors involved and developing advanced treatment processes for removing MPs.Ozonation is one of the most intensively studied and widely used advanced treatment processes for removing MPs. However, due to ozone’s (O3) chemical selectivity, it cannot remove resistant MPs so its use (without additional treatments) results in their release into the environment. Thus, key objectives were to evaluate effects of switching to a new emerging process called electro-peroxone (E-peroxone) on MPs’ removal, by inserting two electrodes into an ozonation reactor. Its potential utility for other applications were also investigated.Paper I addresses effects of upgrading from ozonation to E-peroxone on pharmaceuticals’ removal at lab-scale, using a quantitative structure-activity relationship (QSAR) model. For this purpose, the relationship between QSAR model-predicted second-order rate constants of ozone’s reactions with pharmaceuticals (kO3 values) and ratios of experimentally determined pseudo-first order rate constants of E-peroxone and ozonation (kEP/kOZ values) was examined. Results showed that E-peroxone accelerated the removal of O3-resistant pharmaceuticals. In addition, the QSAR model predicted kO3 values for 491 pharmaceuticals, which suggested that large numbers of pharmaceuticals have high O3 resistance. Paper II addresses the removal of antimicrobials, including biocides and antibiotics, by E-peroxone and ozonation in relation to the water matrix. The results indicated that all studied antibiotics were effectively removed by both processes. In contrast, most of the biocides were at most moderately reactive with ozone, so their removal rate by ozonation was lower. The E-peroxone process increased their removal rate (i.e. removed them much more rapidly) by enhancing formation of hydroxyl radicals (•OH). Paper III reports the design, construction and tests of a pilot-scale mobile E-peroxone and ozonation system for removing naturally occurring MPs in secondary wastewater effluents. The tests included assessments of a new, scalable graphene modified carbon brush cathode for the E-peroxone process, which was found to enhance removal of moderately O3-reactive MPs significantly, and O3-resistant MPs moderately, while consuming similar amounts of electrical energy, or even less, for removing most of the MPs used in the experiments. Paper IV describes the regeneration of spent activated carbon, used for removing ionic MPs, by E-peroxone and ozonation. Both processes restored the activated carbon’s sorption efficiency to similar (or even higher) levels than that of virgin activated carbon, for all tested MPs except perfluorooctanoic acid (PFOA). It was concluded that sorption of MPs on regenerated activated carbon is mainly driven by interactions between ionic forms of the MPs with activated carbon’s charged surfaces rather than their interactions with pores in the activated carbon.
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| 8. |
- Wang, Huijiao, et al.
(författare)
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Oxidation of emerging biocides and antibiotics in wastewater by ozonation and the electro-peroxone process
- 2019
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 235, s. 575-585
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the abatement of a number of antimicrobials frequently detected in municipal wastewater by conventional ozonation and a recently developed ozone-based advanced oxidation process, the electro-peroxone (E-peroxone) process. A synthetic water and a real secondary wastewater effluent were spiked with fourteen antimicrobials, including antibiotics and biocides, and then treated by the two processes. The results show that most of the antibiotics investigated (e.g., ofloxacin, trimethoprim, norfloxacin, and ciprofloxacin) readily react with ozone (O3) and could therefore be efficiently eliminated from the water matrices by direct O3 oxidation during both processes. In contrast, most of the biocides tested in this study (e.g., clotrimazole, pentamidine, bixafen, propiconazole, and fluconazole) were only moderately reactive, or non-reactive, with O3. Therefore, these biocides were removed at considerably lower rate than the antibiotics during the two ozone-based processes, with hydroxyl radical (OH) oxidation playing an important role in their abatement mechanisms. When compared with conventional ozonation, the E-peroxone process is defined by the in situ electrogeneration of hydrogen peroxide, which considerably enhances the transformation of O3 to OH. As a result, the E-peroxone process significantly accelerated the abatement of biocides and required a considerably shorter treatment time to eliminate all of the tested compounds from the water matrices than conventional ozonation. In addition, the E-peroxone process enhanced the contributions of OH fractions to the abatement of moderately ozone reactive benzotriazoles. These results demonstrate that the E-peroxone process holds promise as an effective tertiary treatment option for enhancing the abatement of ozone-resistant antimicrobials in wastewater.
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