Analytical analyses conducted at the Himmerfjärden WWTP (285.000 PE connected) identified 70 pharmaceutical compounds belonging to different therapeutic classes. Such organic micropollutants at low detected concentration range of µg - ng l-1 did not affect the treatment processes at WWTP. Results from analytical studies indicated continuous discharge of organic micropollutants to the surface water with a calculated load amounting to 1.51 kg day-1. Metoprolol, carbamazepine and naproxen were chosen for testing different removal methods. Oxygen Uptake Rate (OUR) tests were conducted to assess the bacterial activity of an activated sludge taken from a full scale aeration plant with the presence of selected target compounds. A semi-technical scale membrane bioreactor ZeeWeed10™, treating final effluent from the Himmerfjärden WWTP (Sweden) was seeded with activated sludge from full scale biological stage. The membrane bioreactor (MBR) system placed after the final treatment appeared to be an insufficient technology for removal of residual amounts of organic micropollutants from WWTP effluents. Batch test studies with activated sludge taken from the membrane bioreactor and with application of granular activated carbon (GAC) filtration resulted in giving an overall assessment of removal efficiency. Metoprolol and carbamazepine tend to be resistant to the biodegradation process and in the dosed high concentration lead to bacterial cell decomposition in the activated sludge. Apparently, removal efficiency for naproxen exceeded the value of 46% with the spiked initial amount of 3.3 mg NAP g-1 MLSS. Application of the GAC filtration proved to be an efficient technique for removal of pharmaceutical compounds from treated wastewater. Application of the statistical programme Modde7 was a time saving tool in studies of fouling occurrence. The effect of fouling phenomenon, which is a highly limiting factor for MBR performance, was minimised by adjusting the operational parameters as predicted by the Modde7 programme. / QC 20101104

Foods contaminated with pathogens are common sources of illness. Currently the most common and sensitive rapid detection methods involve the PCR. However, food matrices are complex and limit the sensitivity and thus detection limits. The use of coated activated carbon can effectively facilitate the removal of PCR inhibitors while not binding targeted bacterial cells from food samples. With activated carbon coated with the optimal amount of milk proteins a cell recovery at pH 7.0 of 95.7 ± 2.0% was obtained, compared to control uncoated activated carbon, which yielded a cell recovery of only 1.1 ± 0.8%. In addition, the milk protein coated activated carbon (MP-CAC) was able to absorb similar amounts of soluble compounds as uncoated activated carbon with the exception of bovine hemoglobin. This is evidence that the use of milk proteins to coat activated carbon should therefore serve as a suitable replacement for bentonite in the coating of activated carbon, which has previously been used for the removal of PCR inhibitors from food. The high amount of PCR inhibitors present in ground beef is a major factor that affects molecular based techniques such as the PCR for the detection of Salmonella enterica. In this study, a novel detection system was developed for eliminating PCR inhibitors and increasing the recovery of S. enterica in ground beef samples with the use of β-cyclodextrin and MP-CAC without enrichment of samples. invA, present in all Salmonella, was used as target the gene in the conventional PCR protocol. With ground beef containing 7.0, 15, and 27 % fat, treatment of stomached samples with 5.0, 10, and 15 % β-cyclodextrin respectively followed by treatment with MP-CAC, resulted in detection of 3 CFU/g which is equivalent to 75 CFU in 25 g samples. The total assay time was 4.5 hr. The methodology described in this study for the detection of S. enterica in ground beef without enrichment is rapid, sensitive, and has the potential to be applied to a number of food matrices to detect low numbers of food-borne bacterial pathogens before product is shipped to prevent costly recalls.

The ongoing energy and environmental crises have pushed the transportation sector, a major greenhouse gas emitter, to seek sustainable fuel and technology alternatives. Natural gas and bio-methane are potential alternatives with numerous advantages over conventional fuels. Adsorbed natural gas (ANG) technology uses porous adsorbent material to store methane efficiently at lower pressures. An issue limiting this technology is the lack of compact tanks with efficient adsorbent packing that increase storage capacity. This study addresses the need for more compact ANG tanks by creating novel binder-less monolithic activated carbon monolith adsorbents with targeted porosity. A template is produced using 3D printing and a commercially available phenolic resin as a filling material. Upon thermal treatment, the 3D-printed template combusts with molecular oxygen in its structure, and the resin is transformed into activated carbon by pyrolysis. Longer activation times led to higher BET surface areas. However, after activation periods beyond 15 minutes, the surface area increase is obtained at the expense of a higher burn-off, which affects the material density. Adsorption of 0.04g/g of methane was measured at 30 bar and 298 K on the activated carbon monolith with the highest BET surface area (516 m2/g). Results in the same conditions on a super high surface area Maxsorb activated carbon were 0.13g/g. Although the methane capacity obtained is lower than in a commercial sample, it was demonstrated that producing an activated carbon monolith with tailored porosity is possible. New techniques for activation should be studied to enhance their gravimetric capacity to make ANG competitive.

Per- and polyfluoroalkyl substances (PFAS) are a large group of anthropogenic compounds with unique properties, including chemical inertness, resistance to many degradation processes and amphiphilic structure. This makes them useful in a range of applications, but also very persistent and bioaccumulative in nature, where PFAS have been linked to adverse health effects in both animals and humans. There are regulations for PFAS, including the REACH regulation and Stockholm Convention, but for now PFAS are monitored individually. This poses a problem since many regulated, long-chain PFAS today are being replaced with unregulated, short-chain homologues with similar hazardous properties.For water remediation of PFAS, a popular and effective sorption technique for their removal is activated carbon (AC), with its close to 100% sorption efficiency. This study focuses on the efficiency of more sustainable materials like bark, steel slag and biochar to sorb eleven different PFAS (PFAS-11) from contaminated water. In this work, contaminated water passed through different constellations of sorbent materials by flow-through experiments, underwent solid-phase extraction (SPE) using a weak anion-exchange (WAX) adsorbent for sample clean-up, and was lastly prepared for analysis using an ultra-performance liquid chromatograph (UPLC) coupled to a quadrupole tandem mass spectrometer (MS/MS).For the different sorbent constellations tested, perfluorooctane sulfonic acid (PFOS) was removed to the highest degree, with an average removal of 70%. When studying the sum of PFAS-11 between the tested sorption constellations, the bark tests sorbed around 20%, the steel slag combinations sorbed between 30-40% and biochar sorbed 43% of the initial PFAS-11 concentration (1 750 ng/L) in the contaminated water. None of these materials achieved an efficient enough sorption to go below the Swedish PFAS-11 drinking water limit value of 90 ng/L, so the results are for the time being suggested more as complementary, low-cost sorption techniques. Further research is recommended to extensively be able to implement more sustainable sorbents with higher sorbing efficiencies.

No description available.

No description available.

Traditional occupational hygiene assessment of occupational exposures to organic gases and vapours rely on low flow (<200 ml/min) NIOSH sorbent tubes. This work investigates 3M charcoal filter media (JK50 and JK40, 3M, Inc.) for collection and analysis of organic vapours across 0.1 ¿ 5 l/min. To enable this work, a custom exposure facility was constructed and validated within which organic analyte gas/vapour concentrations could be introduced at known concentrations while controlling environmental variables such as temperature and humidity and other variables. This facility enabled experiments designed to investigate collection and desorption efficiencies across a range of sample flow rates, temperature and humidity conditions for both NIOSH sorbent tubes (e.g. SKC tube) and 3M charcoal filter media. As a result of the investigations described in this thesis, the following conclusions are drawn. Performance of the 3M charcoal filter media for collection and desorption efficiencies for loading, storage time, humidity and breakthrough at low flow rates (<0.5 l/min) were found comparable to the SKC sorbent tube. It is concluded that 3M charcoal media (JK50 and JK40) are suitable for sampling and analyses of hydrocarbons at flow rates <0.5 l/min. The collection efficiencies of the 3M charcoal filter media were investigated at high flow rates (>0.5l/min) for the same parameters, i.e., loading, temperature and humidity. It is concluded that 3M charcoal filter media can be used with confidence in sampling and analysis of airborne hydrocarbons up to 5 l/min. The Wheeler-Jonas model was found to satisfactorily predict the adsorption kinetics of the 3M charcoal filter media at different loading values of hydrocarbons. It was therefore concluded that the model can be applied to determine the suitable amount of 3M charcoal filter media prior to sampling for a given loading.

An experimental pressure swing adsorption unit has been constructed and used to investigate the separation of carbon dioxide from carbon dioxide enriched air using both an activated carbon and a type 5A molecular sieve adsorbent. Continuous, cyclic operation was achievedusing a pair of fixed bed adsorbers. At any one time the feed gas entered one bed at a high pressure and part of the purified gas was returned to the other bed at a reduced pressure to provide countercurrent regeneration of the adsorbent. The beds of adsorbent used were each nominally 0.165m diameter and Im. deep. Separations were carried out at approximately ambient temperature using air flow rates in the range 0.15 to 0.95 kg/m2s and inlet carbon dioxide concentrations'in the range 0.1 to 1.5% v/v. Adsorption pressures of 2 to 6.4 bar were examined, the desorption pressure being maintained throughout at essentially 1.0 bar. The period time was varied from 30 to 900 seconds and the revert ratio (i. e. the ratio of the product gas returned for desorption to the total feed rate to the unit) was varied from 0 to 1.0. The carbon dioxide separation efficiency was found to increase markedly as the adsorption pressure and the revert ratio were increased whereas it was relatively insensitive to variations in feed rate and, more particularly, feed concentration. The performance of the molecular sieve adsorbent was found to be very sensitive to the presence of moisture in the feed gas. In contrast the carbon dioxide efficiencies observed with Lhe activated carbon were unaffected by the presence of small amounts (circa 100 ppm) of moisture in the feed. A theoretical model has been proposed for predicting the performance of pressure swing adsorption systems of the type investigated and approximate analytical equations and more precise numerical techniques have been established to represent its solution. The approximate analytical solutions were found to give close agreement with the more precise methods examined under conditions corresponding to low values of a dimensionless period time parameter. The proposed theoretical model incorporates an effective irean mass transfer coefficient to represent the diffusion process within the adsorbent particles. Methods for estimation of the value of this coefficient based on the limiting conditions of a periodic constant surface flux or a periodic constant surface concentration are presented. The experimental performance data were analysed in terms of the proposed analytical solution to give values of the apparent solid phase mass transfer coefficient for comparison with those predicted theoretically. In general the apparent experimental values were consistently less than the predicted values. In addition the relationship between the experimental and predicted coefficients was found to be dependent on both the nature of the adsorbent and a parameter formed by the product of the revert ratio and the adsorption to desorption pressure ratio. Empirical correlating equations which incorporate this dependence are presented.

Electrochemical supercapacitors (ECs) attract significant attentions for their unique characteristics of high power density, good cycling capability and low cost. This dissertation will focus on fabrication of composite materials for electrodes and devices of ECs. A conceptually new colloidal approach to the fabrication of metal oxide – multiwalled carbon nanotube (MWCNT) composites is proposed. The heterocoagulation of positively charged oxide nanoparticles and negatively charged MWCNT allows the fabrication of advanced nanocomposites with improved dispersion of individual components. The proof-of-principle was demonstrated by the fabrication of MnO2-MWCNT electrodes for ECs with excellent performance. We proposed another novel concept based on electrostatic heterocoagulation of MnO2-MWCNT composites in aqueous environment. In this case, Benzyldimethylhexadecylammonium chloride (BAC) surfactant and caffeic acid (CA) were selected for adsorption and dispersion of MWCNT and MnO2, respectively, and this allowed the formation of stable aqueous suspensions of positively charged MWCNT and negatively charged MnO2. The asymmetric device showed high capacitance, high powerenergy characteristics with enlarged voltage window of 1.8 V, good capacitance retention at high charge-discharge rates and cyclic stability. A novel capacitive material BiMn2O5 was firstly discovered and synthesized for ECs applications in our studies. The BiMn2O5 nanocrystals were prepared by a hydrothermal method. We demonstrated for the first time that BiMn2O5 – MWCNT composite can be used as a new active material for positive electrodes of ECs. The composite electrode with high mass loading showed a capacitance of 6.0 F cm-2 (540 F cm-3) at a scan rate of 2 mV s-1 and excellent capacitive behavior at high scan rates. As-fabricated device showed good cyclic stability in a voltage window of 1.8 V with energy density of 13.0 Wh L-1 (9.0 Wh kg-1) and power density of 3.6 kW L-1 (2.5 kW kg-1). We firstly discovered that Poly[1-[4-(3-carboxy-4 hydroxyphenylazo)benzenesulfonamido]- 1,2-ethanediyl, sodium salt] (PAZO) can be used as an universal dispersant for various materials and its thin film fabricated by electrophoretic deposition (EPD) exhibited photo-induced birefringence. Our new findings indicated that PAZO is good candidate for diverse materials dispersing because it contains diaromatic monomers with salicylate ligands, which can provide multiple adsorption sites for efficient adsorption on particles and impart electrical charges to the particles. Additionally, the use of PAZO polymer offers the advantages of improved steric stabilization. We discovered that Celestine blue (CB) can be developed as an efficient dispersing agent for the nanoparticles. We found that CB includes a catechol ligand, which can provide CB adsorption on inorganic nanoparticles. The relatively large size of the CB molecules is beneficial for the electrosteric dispersion. The benefits of cathodic EPD for nanotechnology were demonstrated by the formation of nanostructured MnO2 films on commercial high surface area current collectors for energy storage in ECs. / Thesis / Doctor of Philosophy (PhD)

In this study, polypyrrole (PPy) prepared by chemical and electrochemical polymerization was investigated as the electrode of electrochemical supercapacitor (ES). New strategies were developed for the fabrication of nano-structured PPy and PPy based nano-composites, which included discovery of advanced anionic dopants and multi-functional nano-crystals, and development of co-dispersing agents. These methods improved the capacitive performance and cycle stability of PPy electrodes. The results indicated that high material loading and good capacitance retention of PPy was achieved using an electrochemical polymerization method and Ni plaque as the current collectors. Nano-crystalline (CTA)2S2O8 formed by a chemical precipitation method from solutions, containing anionic oxidant (S2O82-) and cationic surfactant (CTA+), could be used as the oxidant to synthesize PPy nano-fibers. We demonstrated that multi-wall carbon nanotubes (MWCNT) can be efficiently dispersed using such nano-crystals. Application of multi-functional nano-crystals is a conceptually new approach for the fabrication PPy coated MWCNT. Moreover, safranin and malachite green were found as universal dispersing and charging agents for cataphoretic deposition of graphene, MWCNT and PPy nano-fibers. It opens new strategies in colloidal and electrochemical processing of PPy nano-composites for ES electrodes. PPy coated MWCNT, prepared by the multi-functional nano-crystals (CTA)2S2O8, was employed for the fabrication of N-doped activated carbon-coated MWCNT (N-AC-MWCNT). The obtained N-AC-MWCNT was uniformly coated and possessed with high surface area. The use of N-AC-MWCNT enabled the fabrication of ES electrodes with high mass loading and high active material to current collector mass ratio. Symmetric and asymmetric ES cells, fabricated by N-AC-MWCNT and aqueous Na2SO4 electrolyte, showed high specific capacitance, good capacitance retention and large voltage window. The positive electrode of asymmetric ES, MnO2 coated MWCNT, was successfully prepared by the chemical reaction between KMnO4 and N-AC-MWCNT. The problem of degradation of MWCNT was avoided by the use of N-AC as the sacrificial carbon. Significant progress on ES technology has allowed for the development of capacitive dyes removal (CDR) methods using ES devices. In our study, porous carbon materials, N-doped activated carbon coated MWCNT (N-AC-MWCNT) and N-doped activated carbon nano-fibers (N-AC-NF), were developed as the electrodes for CDR applications. The experimental results indicated that capacitive performance of ES cells was influenced by the chemical structure, size, charge-to mass ratio, concentration and redox-active ligands of the dyes. CDR is a promising method for removal of various cationic and anionic dyes, which offers advantages of energy saving and simple electrode regeneration. / Thesis / Doctor of Philosophy (PhD)