scholarly journals Photocatalytic degradation of caffeine in a slurry reactor with intermittent UV irradiation: optimization and response surface modelling

2021 ◽  
Author(s):  
C. Nirmala Rani
Keyword(s):  
Photocatalytic Degradation ◽  
Response Surface ◽  
Oxygen Demand ◽  
Surface Modelling ◽  
Initial Concentration ◽  
Design Expert ◽  
First Order ◽  
First Order Kinetics ◽  
Response Surface Modelling ◽  
Catalyst Dosage

Abstract This study focusses on the photocatalytic degradation of caffeine (CAF) a stimulating drug and environmental contaminant that pose threat to humans and the environment. The effect of operating parameters such as; CAF initial concentration (5–20 mg/L), catalyst dosage (0.1–0.9 g/L) and pH (3.0–9.0) were explored in detail. The experimental results showed the maximum CAF and chemical oxygen demand (COD) removals of 87.2% and 66.7% respectively. The optimized parameters were; CAF initial concentration – 5 mg/L, catalyst dosage – 0.5 g/L and pH – 7.2. The photocatalytic degradation of CAF followed pseudo-first order kinetics. The obtained experimental data were analysed with response surface methodology (RSM) using Design Expert Software.

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts

2013 ◽  
Vol 69 (6) ◽  
pp. 1219-1226
Author(s):  
C. Chen ◽  
Q. Xie ◽  
B. Q. Hu ◽  
X. L. Zhao
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Degradation Rate ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Solution Ph ◽  
First Order ◽  
First Order Kinetics ◽  
Catalyst Dosage ◽  
H2o2 Addition

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol–gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

scholarly journals Degradation and mineralization of violet-3B dye using C-N-codoped TiO2 photocatalyst

2019 ◽  
Vol 25 (4) ◽  
pp. 529-535 ◽  
Author(s):  
Reza Audina Putri ◽  
Safni Safni ◽  
Novesar Jamarun ◽  
Upita Septiani ◽  
Moon-Kyung Kim ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Sol Gel ◽  
Organic Dye ◽  
Halogen Lamp ◽  
Acidic Ph ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Catalyst Dosage

The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO<sub>2</sub> catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO<sub>2</sub> followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L<sup>-1</sup> violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO<sub>2</sub> catalyst, and approximately 44% TOC was removed as a result of the mineralization.

scholarly journals Electro-photocatalytic degradation of amoxicillin using calcium titanate

2018 ◽  
Vol 16 (1) ◽  
pp. 949-955 ◽  
Author(s):  
Lvshan Zhou ◽  
Xiaogang Guo ◽  
Chuan Lai ◽  
Wei Wang
Keyword(s):  
Photocatalytic Degradation ◽  
Reaction Rate ◽  
Irradiation Time ◽  
Oxygen Demand ◽  
Reaction Rate Constant ◽  
Calcium Titanate ◽  
Experimental Conditions ◽  
Exponential Factor ◽  
First Order ◽  
First Order Kinetics

AbstractThe electro-photocatalytic degradation of amoxicillin in aqueous solution was investigated using single factor test by the potassium permanganate method for measuring the values of chemical oxygen demand (CODMn). Batch experiments were carried out successfully under different conditions, including initial amoxicillin concentration, calcium titanate dosage, pH, UV irradiation time, electrolyte and temperature. The experimental results show that there is a great difference between electro-photocatalytic and photocatalitic degradation. The maximum electro-photocatalytic degradation efficiency can increase to 79% under the experimental conditions of 200 mL amoxicillin solution (100 mg L-1) with 0.5 g calcium titanate by pH=3 for 120 min irradiation and 0.058 g sodium chloride as electrolyte at 318.5K. In addition, the reaction rate constant of 0.00848~0.01349 min-1, activation energy of 9.8934 kJ mol-1 and the pre-exponential factor of 0.5728 were obtained based on kinetics studies, indicating that the electro-photocatalytic reaction approximately followed the first-order kinetics model.

Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
Author(s):  
Xin Tong ◽  
Jiao Li ◽  
Jun Ma ◽  
Xiaoquan Chen ◽  
Wenhao Shen
Keyword(s):  
Degradation Rate ◽  
Southern China ◽  
Catalytic Degradation ◽  
Pulp And Paper ◽  
Gaseous Pollutants ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

Effects of initial concentration and irradiation dose to degradation of di butyl phthalate from phosphoric acid (30 % P2O5)

2018 ◽  
Vol 106 (11) ◽  
pp. 909-916
Author(s):  
Louisa Bounemia ◽  
Abdelhamid Mellah
Keyword(s):  
Organic Matter ◽  
Phosphoric Acid ◽  
Optimal Recovery ◽  
Γ Irradiation ◽  
Γ Radiation ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Butyl Phthalate

Abstract The pretreatment of the phosphoric acid is a stage of utmost importance leading to an optimal recovery of the uranium present in this acid. To this end, the degradation of the organic matter which obstructs considerably this recovery was tested by γ irradiation. This study lies within the scope of the radiation/matter interaction; concerning the use of the γ irradiator as proceed of phosphoric acid purification by the degradation of di butyl phthalate (DBP). Studies of the interaction of γ radiation with phosphoric acid solutions polluted by an organic matter concern the study of the influence of some parameters such as: dose rate (0.5–35 kGy), initial concentration (50–500 mg/L) of the pollutant, pH and % in P2O5 on the degradation of organic matter by γ irradiation. The reactions followed pseudo first order kinetics for different initial concentrations. The results made it possible to say that the degradation of di butyl phthalate by γ irradiation is dependent on the amount of the concentration of DBP and pH. The G-values decreased with absorbed doses, and increased with higher initial concentrations.Purification of phosphoric acid by γ radiation does not degrade the quality of this acid.

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