Chavalit Ratanatamskul

Chemical oxidation of 2,6-dimethylaniline in the fenton process.

2,6-Dimethylaniline degradation by Fenton process has been studied in depth for the purpose of learning more about the reactions involved in the oxidation of 2,6-dimethylaniline under various reaction conditions. The effect of reaction conditions including the initial pH value, and the dosages of ferrous ions and hydrogen peroxide on 2,6-dimethylaniline and COD removal were investigated. 2,6-Dimethylaniline removal efficiency of 70% was achieved under optimal reaction conditions of pH value of 2, dosage of 2 mM of ferrous ion, and 20 mM of hydrogen peroxide after 3 h. A series of intermediates were identified, corresponding to ring compounds and short-chain organic acids. The intermediates were 2,6-dimethylphenol, 2,6-dimethylnitrobenzene, 2,6-dimethylbenzoquinone, 3-hexanone, maleic acid, acetic acid, formic acid, and oxalic acid. An oxidation pathway of the target organic was also proposed in this study.

Chemical oxidation of 2,6-dimethylaniline by electrochemically generated Fenton's reagent.

Oxidation of 2,6-dimethylaniline by electro-Fenton process in acidic solution at pH 2 was investigated. The effects of pH, Fe(2+), H(2)O(2) and current density were assessed to determine the optimum operating parameters. The oxidation efficiency of 2,6-dimethylaniline was determined by the reduction of 2,6-dimethylaniline, COD and TOC in the solutions. Results reveal that 1 mM of 2,6-dimethylaniline can be completely degraded in 4 h with 1 mM of Fe(2+) and 20 mM of H(2)O(2) and current density of 15.89 A m(-2) at pH 2. The highest COD and TOC removal were observed when 120 mM of hydrogen peroxide was applied. Consequently, the electro-Fenton process is a reliable alternative in the degradation of 2,6-dimethylaniline. 2,6-dimethylphenol, 2,6-dimethylnitrobenzene, 2,6-dimethylbenzoquinone, 3-hexanone, lactic acid, oxalic acid, acetic acid, maleic acid and formic acid were detected during the degradation of 1 mM of 2,6-dimethylaniline solution by electro-Fenton method. A reaction pathway that includes these products is proposed for 2,6-dimethylaniline degradation.

Kinetics of 2,6-dimethylaniline oxidation by various Fenton processes.

The kinetics of 2,6-dimethylaniline degradation by Fenton process, electro-Fenton process and photoelectro-Fenton process was investigated. This study attempted to eliminate the potential interferences from intermediates by making a kinetics comparison of Fenton, electro-Fenton and photoelectro-Fenton methods through use initial rate techniques during the first 10 min of the reaction. Exactly how the initial concentration of 2,6-dimethylaniline, ferrous ions and hydrogen peroxide affects 2,6-dimethylaniline degradation was also examined. Experimental results indicate that the 2,6-dimethylaniline degradation in the photoelectro-Fenton process is superior to the ordinary Fenton and electro-Fenton processes. Additionally, for 100% removal of 1mM 2,6-dimethylaniline, the supplementation of 1mM of ferrous ion, 20mM of hydrogen peroxide, current density at 15.89 A m(-2) and 12 UVA lamps at pH 2 was necessary. The overall rate equations for 2,6-dimethylaniline degradation by Fenton, electro-Fenton and photoelectro-Fenton processes were proposed as well.

Removal of COD and colour from old-landfill leachate by Advanced Oxidation Processes

This research aims to apply Advanced Oxidation Processes (AOPs) using ozonation, combined O3/H2O2 and Fenton reaction for simultaneous COD and colour removal from old-landfill leachate. The efficiencies of the AOPs for both COD and colour removal could be ranked in this order; Fenton reaction > O3/H2O2 > O3. The Fenton reaction, operated at pH 3 could significantly remove more than 85% of colour and 80% of COD from the leachate. Fenton reaction could also enhance biodegradability of the old-landfill leachate. Moreover, the reaction rates of these AOP processes for COD and colour removal were found to follow the second-order kinetics.

Effect of carrier composition on 2,6‐dimethylaniline degradation in aqueous solution by fluidized‐bed Fenton process

The fluidized‐bed Fenton process is an alternative process that decreases iron sludge from the Fenton reaction by using carriers to crystallize iron on to the surface of the carrier. In this study, the target compound is 2,6‐dimethylaniline, which is a carcinogen and difficult to degrade. This study examined the effect of different carriers on the degradation of 2,6‐dimethylaniline by a fluidized‐bed Fenton process. The six carriers were alumina dioxide (Al2O3), silica dioxide (SiO2), and black, white, brown and coloured gravels. The results revealed that differences in the composition of elements and the structures of each carrier have different effects on the oxidation of 2,6‐dimethylaniline. The carriers containing Ca were not suitable for use in the fluidized‐bed Fenton process. In contrast, Al2O3 and SiO2 were more efficient at removing 2,6‐dimethylaniline, and the pH value was almost stable. Moreover, 2,6‐dimethylanililne removal efficiency of Al2O3 was higher compared with the other carriers. Therefore, in this study, Al2O3 was an optimum carrier for the oxidation of 2,6‐dimethylaniline.

Performance of biological powder activated carbon-membrane bioreactor (BPAC-MBR) for old-landfill leachate treatment.

This research aims to investigate the performance of the combined BPAC-MBR system for old-landfill leachate treatment. The system was operated at two different intermittent aeration modes (aeration or non-aeration) of 120-120 min and 150-150 min. It was found that the BPAC-MBR system operating at 150-150 min could give higher removal efficiencies for all parameters; COD at 83%, colour at 85%, TKN at 97%, and TP at 68%. The reason might be that the degradation mechanism of microorganisms inside the BPAC-MBR system needed sufficient time for sequential aerobic and anaerobic periods to improve biodegradation for slowly biodegradable organic compounds.

A prototype IT/BF–MBR (inclined tube/biofilm-membrane bioreactor) for high-rise building wastewater recycling

AbstractA novel inclined-tube biofilm-membrane bioreactor (IT/BF-MBR) has been developed in a prototype system for high-rise building wastewater recycling. The prototype IT/BF-MBR system was designed as a single compact reactor with three compartments, starting from first-stage biofilm compartment, second-stage biofilm compartment and aerobic membrane compartment with submerged MF membrane installation. Here, the inclined tube was installed as a prefilter for sieving and filtering the incoming suspended solid and also served as a media to promote biofilm growth in the biofilm compartments to enhance more biomass activity inside the IT/BF-MBR system. The system received raw wastewater from a 20-floor university building at a design flow rate capacity of 4 m3/day. The IT/BF-MBR could achieve stable treatment performance as above 90% removal efficiencies for organic Chemical oxygen demand, NH4+–N, and total phosphorus. The composition of microbial EPS inside the membrane bioreactor system was found in the fo...

Effect of operating parameters on triclosan degradation by Fenton’s reagents combined with an electrochemical system

AbstractTriclosan is used as an antimicrobial in many processes. Fenton’s reagents were used to degrade triclosan in combination with an electrochemical system, and the effects of operating parameters were investigated. The pH, current density, Fenton’s reagents ratio, and H2O2 feeding modes were investigated to determine their effect on the process efficiency. The results showed that higher efficiency could be achieved by increasing the H2O2 concentration during Fenton’s reagents ratio modification and by changing the H2O2 feeding mode development from a one-time initial feeding mode to a step feeding mode of operation. This could also reduce the toxicity potential of the one-time initial feeding mode. Under optimum pH, Fenton’s reagents ratio, and electrical current density conditions, 1 mM triclosan could be completely removed in the initial H2O2 feeding operation. Additionally, the initial degradation rate for the first-order model and relative oxidation performance ratio was used to indicate process ...

Effects of organic loading rate and operating temperature on power generation from cassava wastewater by a single-chamber microbial fuel cell

AbstractThis research examined the effects of organic loading rate (OLR) and operating temperature on cassava wastewater treatment and the resulting power generated by a single-chamber microbial fuel cell. The OLRs were controlled to be 0.56, 1.44, 2.79, 4.14, and 6.25 kg COD/m3 d at neutral pH 7.0. The selected operating temperatures were at normal mesophilic range at 30°C and a transition temperature range between mesophilic and thermophilic at 45°C. The maximum efficiency of COD removal achieved from the OLR at 0.56 kg COD/m3 d was 91.44 ± 0.72 and 90.72 ± 0.87% at 30 and 45°C, respectively. While the maximum power density obtained from the OLR at 6.25 kg COD/m3 d was 28.68 and 27.85 W/m3, respectively. The performance of COD removal decreases with increasing OLR. The power densities, the coulombic efficiency, and the internal resistance increases with decreasing OLR.

The energy-saving anaerobic baffled reactor membrane bioreactor (EABR-MBR) system for recycling wastewater from a high-rise building

A novel energy-saving anaerobic baffled reactor-membrane bioreactor (EABR-MBR) system has been developed as a compact biological treatment system for reuse of water from a high-rise building. The anaerobic baffled reactor (ABR) compartment had five baffles and served as the anaerobic degradation zone, followed by the aerobic MBR compartment. The total operating hydraulic retention time (HRT) of the EABR-MBR system was 3 hours (2 hours for ABR compartment and very short HRT of 1 hour for aerobic MBR compartment). The wastewater came from the Charoen Wisawakam building. The results showed that treated effluent quality was quite good and highly promising for water reuse purposes. The average flux of the membrane was kept at 30 l/(m2h). The EABR-MBR system could remove chemical oxygen demand, total nitrogen and total phosphorus from building wastewater by more than 90%. Moreover, it was found that phosphorus concentration was rising in the ABR compartment due to the phosphorus release phenomenon, and then the concentration decreased rapidly in the aerobic MBR compartment due to the phosphorus uptake phenomenon. This implies that phosphorus-accumulating organisms inside the EABR-MBR system are responsible for biological phosphorus removal. The research suggests that the EABR-MBR system can be a promising system for water reuse and reclamation for high-rise building application in the near future.