Roland Haseneder

Photochemical oxidation of p-chlorophenol by UV/H2O2 and photo-Fenton process. A comparative study.

In this study, photochemical advanced oxidation processes (AOPs) utilizing the combinations of UV/H2O2 and the photo-Fenton reaction (UV + classical Fenton reaction) were investigated in lab-scale experiments for the degradation of p-chlorophenol. The study showed that the photo-Fenton process, (a mixture of hydrogen peroxide and ferrous or ferric ion), was the most effective treatment process under acidic conditions and produced a higher rate of degradation of p-chlorophenol at a very short radiation time. It accelerated the oxidation rate by 5-9 times the rate for the UV/H2O2 process. The reaction was found to follow the first order, the reaction was influenced by the pH, the input concentration of H2O2 and the amount of the iron catalyst and the type of iron salt. The experimental results showed that the optimum conditions were obtained at a pH value of 3, with 0.03 mol/l H2O2, and 1 mmol/l Fe(II) for the UV/H2O2/Fe(II) system and 0.01 mol/l H2O2 and, 0.4 mmol/l Fe(III) for the UV/H2O2/Fe(III) system. The reactions were accompanied by the generation of Cl- which reached its maximum value at a short reaction time when using the photo-Fenton process. Finally a rough comparison of the specific energy consumption shows that photo-Fenton process reduced the energy consumption by at least 73 to 83% compared with the UV/H2O2 process.

The application of membrane filtration for the removal of ammonium ions from potable water.

It is well recognized that soluble ammonia and nitrite in drinking water has chronic effects on humans. Ammonia has potential environmental health hazards, particularly to young children. European Union Standards limit the concentration of ammonia to 0.5 mg/l in drinking water. In Eskisehir (Turkey) drinking and tap water are supplied from a water treatment plant, consisting mainly of screening, sedimentation, filtration and sterilization units and having a capacity of 80.000 m3/d. Depend on the industrial and climatic effects the observed high ammonium concentration in treated water causes undesirable effects of water quality. Therefore, people in Eskisehir do not want to use tap water for drinking. The aim of the study was to evaluate the performance of membrane processes, i.e. Nanofiltration and reverse osmosis to the removal of ammonium and Ca ions from plant effluent and recommend one of them for a subsequent pilot plant application.

Optimization Study for Treatment of Acid Mine Drainage Using Membrane Technology

The use of membrane technology in the treatment of Acid Mine Drainage (AMD) can result in reduction of chemical usage and sludge production making the treatment process more environmentally friendly. This study deals with the optimization of membrane filtration performance in the treatment of AMD using two nanofiltration (NF) membranes (NF99 and DK) and one reverse osmosis (RO). All membranes were used in various tests treating a model solution at two different concentration levels in order to cover the concentration of actual AMD found in the mining industry. The main parameters which were studied to determine the optimal condition for AMD filtration are pressure, pH, temperature, and flow rate. Pressure and temperature were found to have a considerable influence on flux, while rejection was only slightly influenced by pressure. The feed flow rate had no effect on rejection. The highest flux with moderate rejection was determined for NF99 while RO had the lowest flux but highest rejection. Therefore, NF is preferable for AMD treatment due to lowest energy consumption. The treatment has also been tried on a large scale to check its applicability at a commercial scale. Finally, PHREEQC has been used to determine the scaling risk in the prepared AMD.

Aromatic Compounds Degradation In Water By Using Ozone And AOPs. A Comparative Study. O-Nitrotoluene As A Model Substrate

Abstract O-Nitrotoluene lpar;C7H7NO2) was used as a model compound to study the oxidation of aromatic volatile organic chemicals. Bench-scale studies were conducted to assess the efficiency of ozonation (O3) and advanced oxidation processes (AOPs) such as O3/UV, O3/H2O2, UV/H2O2, and O3/UV/H2O2 for the treatment of o-Nitrotoluene as one of die benzene derivatives. Results of this study indicated that the direct reaction between o-Nitrotoluene and ozone resulted in a slow oxidation rate of o-Nitrotoluene and was pseudo first order. At higher pH, or by the combination of ozone with UV or H2O2 ozonation resulted in more efficient and faster oxidation rates of o-Nitrotoluene due to the participation of hydroxyl radicals in the oxidation of o-Nitrotoluene. Consistent results were observed for O3/UV and UV/H2O2 treatment. The reaction kinetics and mass transfer were also studied.

TDS STUDY OF CO2 ADSORPTION ON K-PROMOTED FE(110)

Thermal desorption spectroscopy has been used to detect the gaseous products which are formed in the coadsorbed layer of potassium and carbon dioxide on Fe(llO) in dependence on both potassium coverage and temperature. The chemical nature of the desorbed species (C02 and CO) as well as their desorption temperatures depend on the potassium coverage. The results are in excellent agreement with predictions made on the basis of quantitative evaluation of Oli XP spectra in a preceding paper.

Development of a hybrid water treatment process using forward osmosis with thermal regeneration of a surfactant draw solution

AbstractA hybrid process of forward osmosis (FO) in combination with thermal regeneration of the draw solution is proposed and investigated experimentally. On the side of the draw solution, a surfactant water emulsion is contacting the FO membrane. The solubility of non-ionic surfactants in water is exceptional in that it decreases at elevated temperatures. Depleted surfactant/water draw solution can thus easily be separated into an aqueous phase (product water) and a surfactant-rich phase (regenerated draw solution) by increasing temperature in order to induce liquid phase separation. The optimal choice of a surfactant as active draw agent will need to account for the surfactants performance in the thermal separation as well as in FO. In this work, 12 different surfactants were evaluated and discussed for their usability as draw solution. The surfactant L31 showed the best performance considering both criteria: high affinity toward water in FO and the lowest temperatures in thermal regeneration at 50°C. ...

Nanofiltration of uranium-contaminated water – focus on separation mechanisms

Nanofiltration offers new perspectives for the treatment of mine drain-age from former uranium mines, e.g. in East Germany. In this study the performance of various commercial nanofiltration membranes for a real mine water sample was determined experimentally and modelled. Experimental data is key to membrane selection and is necessary to validate modelling results. Mathematical modelling offers deeper insights into the interaction of uranium species with solid surfaces which also has the potential to extrapolate to other research fields.