scholarly journals UV Light-Irradiated Photocatalytic Degradation of Coffee Processing Wastewater Using TiO2 as a Catalyst

Environments ◽  
2020 ◽  
Vol 7 (6) ◽  
pp. 47 ◽  
Author(s):  
Gurudev Sujatha ◽  
Subramaniam Shanthakumar ◽  
Fulvia Chiampo
Keyword(s):  
Photocatalytic Degradation ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Ultraviolet C ◽  
Catalyst Dosage ◽  
Uv C ◽  
Experimental Runs

The coffee industry generates a significant amount of wastewater that is rich in organic loads and is highly acidic. The present study investigates the potential of the heterogeneous photocatalytic oxidation process to reduce the pollutant load in coffee processing wastewater. The experimental runs were conducted to evaluate the effect of operative parameters such as pH, catalyst dosage, intensity of UV light irradiation, and addition of oxidant on Chemical Oxygen Demand (COD) and colour reduction. Significant results for COD and colour removal, 67%, and 70% respectively, were achieved at a pH of 4 with titanium dioxide (TiO2), and a catalyst dosage of 500 mg/L, using four ultraviolet-C (UV-C) lamps of 16 W each. With the addition of hydrogen peroxide (H2O2) as an oxidant, the removal efficiency increased to 84% and 75% for COD and colour, respectively. Finally, the best results obtained by photocatalytic degradation using UV light were compared to those using solar light. Based on the investigation, it was inferred that the pollutant removal efficiency in coffee pulping wastewater was also considerably high under sunlight. These findings may have relevance in terms of application in countries where coffee processing is carried out and where sunlight irradiance is usually strong: the technique could be exploited to decrease the pollutant content of this wastewater sustainably.

scholarly journals Removal of 17β-Estradiol (E2) from Aqueous Solutions Using Potassium Permanganate Combined with Ultraviolet (KMnO4/UV)

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Monirah Ataee ◽  
Abdolmajid Fadaei ◽  
Gashtasb Mardani ◽  
Morteza Sedehi
Keyword(s):  
Humic Substances ◽  
Removal Efficiency ◽  
Oxygen Demand ◽  
Aqueous Environment ◽  
Order Kinetic ◽  
Kinetic Reaction ◽  
Optimum Ph ◽  
Ultraviolet C ◽  
17Β Estradiol ◽  
Uv C

17β-Estradiol (E2) has a significant health risk to humans, even at the ng/L level, and is discharged to the aqueous environment through wastewater. Advanced oxidation processes were proposed as an efficient process for the removal of E2. In this study, a combination of ultraviolet-C (UV-C) and KMnO4 was applied for the removal of E2. Results have shown that the removal efficiency of E2 in pH 4 (acidic condition) was 93.80 ± 0.42%. But, removal efficiency in neutral (7) and alkaline (10) conditions was 78.3 ± 2.12% and 84 ± 0.71%, respectively. The effect of Fe+2, Ca+2, Mg+2, Mn+2, and Fe+3 ions (1 mg/L) was investigated in optimized pH (4). Mn+2, Fe+2, and Ca+2 ions enhanced the removal efficiency to 94.8 ± 0.84%, 95.55 ± 0.07%, and 94.7 ± 0.14%, respectively p > 0.05 , while Mg+2 and Fe+3 ions decreased the removal efficiency significantly to 76.15 ± 1% and 83.91 ± 0.3% p < 0.05 . The efficiency of E2 removal in the presence of 5 mg/L of PAC reduced significantly to 85 ± 4.24% p < 0.05 . Also, humic substances like humic acid, fulvic acid, and a combination of them could enhance the efficiency to 99.87 ± 0.01%, 99.9 ± 0.06%, and 99.93 ± 0.014%, respectively p > 0.05 . The result indicates that the rate of oxidation of E2 is related to the second exponent of the initial concentration of E2 for optimum pH and the presence of all ions. But, in the presence of humic substances, the first-order kinetic reaction was best applicable in describing oxidation of E2. Removal of chemical oxygen demand for E2 after 120 minutes’ of contact time at optimum pH (86 ± 4.2%) demonstrated mineralization of these compounds at acceptable levels. Results presented that the UV-C/KMnO4 process is efficient for the removal of hormones from the aqueous solution.

Biogeochemical indicators to evaluate pollutant removal efficiency in constructed wetlands

1997 ◽  
Vol 35 (5) ◽  
pp. 1-10 ◽  
Author(s):  
K. R. Reddy ◽  
E. M. D'Angelo
Keyword(s):  
Microbial Biomass ◽  
Removal Efficiency ◽  
Nitrate Removal ◽  
Oxygen Demand ◽  
Acid Soils ◽  
Pollutant Removal ◽  
Alkaline Soils ◽  
Organic C ◽  
Wetland Treatment ◽  
Biogeochemical Indicators

Wetlands support several aerobic and anaerobic biogeochemical processes that regulate removal/retention of pollutants, which has encouraged the intentional use of wetlands for pollutant abatement. The purpose of this paper is to present a brief review of key processes regulating pollutant removal and identify potential indicators that can be measured to evaluate treatment efficiency. Carbon and toxic organic compound removal efficiency can be determined by measuring soil or water oxygen demand, microbial biomass, soil Eh and pH. Similarly, nitrate removal can be predicted by dissolved organic C and microbial biomass. Phosphorus retention can be described by the availability of reactive Fe and Al in acid soils and Ca and Mg in alkaline soils. Relationships between soil processes and indicators are useful tools to transfer mechanistic information between diverse types of wetland treatment systems.

scholarly journals TiO2 BEADS FOR PHOTOCATALYTIC DEGRADATION OF HUMIC ACID IN PEAT WATER

2011 ◽  
Vol 11 (3) ◽  
pp. 253-257 ◽  
Author(s):  
Winarti Andayani ◽  
Agustin N M Bagyo
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Oxalic Acid ◽  
Chemical Oxygen Demand ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Color Intensity ◽  
Before And After

Degradation of humic acid in aqueous solution containing TiO2 coated on ceramics beads under irradiation of 254 nm UV light has been conducted in batch reactor. The aim of this experiment was to study photocatalytic degradation of humic acid in peat water. The irradiation of the humic acid in aqueous solution was conducted in various conditions i.e solely uv, in the presence of TiO2-slurry and TiO2 beads. The color intensity, humic acid residue, conductivity and COD (chemical oxygen demand) of the solution were analyzed before and after irradiation.  The compounds produced during photodegradation were identified using HPLC. The results showed that after photocatalytic degradation, the color intensity and the COD value of the solution decreased, while the conductivity of water increased indicating mineralization of the peat water occurred. In addition, oxalic acid as the product of degradation was observed.

scholarly journals Impact of Room Location on UV-C Irradiance and UV-C Dosage and Antimicrobial Effect Delivered by a Mobile UV-C Light Device

2016 ◽  
Vol 37 (6) ◽  
pp. 667-672 ◽  
Author(s):  
John M. Boyce ◽  
Patricia A. Farrel ◽  
Dana Towle ◽  
Renee Fekieta ◽  
Michael Aniskiewicz
Keyword(s):  
Staphylococcus Aureus ◽  
Stainless Steel ◽  
Prospective Observational Study ◽  
Uv Light ◽  
Antimicrobial Effect ◽  
M 10 ◽  
Surgical Ward ◽  
Ultraviolet C ◽  
Vancomycin Resistant ◽  
Uv C

OBJECTIVETo evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device.DESIGNProspective observational study.METHODSWe used 6 UV light sensors to determine UV-C irradiance (W/cm2) and UV-C dosage (µWsec/cm2) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA.RESULTSMean UV-C irradiance was nearly 1.0E-03 W/cm2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P<.001). Mean UV-C dosages received by UV-C sensors located at different distances and orientation relative to the device varied significantly during 5-minute cycles and during 15-minute cycles (P<.001). Log10 reductions ranged from >4 to 1–3 for MRSA, >4 to 1–2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles.CONCLUSIONUV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device.Infect Control Hosp Epidemiol 2016;37:667–672

scholarly journals Cost-Effective Disinfection Robot Using UVC Radiation

2021 ◽  
Vol 40 ◽  
pp. 02003
Author(s):  
Mansi Dhikle ◽  
Vinaya Dharne ◽  
Pankaja Gaikar ◽  
Kausar Fakir
Keyword(s):  
Video Streaming ◽  
Uv Light ◽  
Low Cost ◽  
Cost Effective ◽  
Live Video ◽  
Medical Facilities ◽  
Ultraviolet C ◽  
Cleaning Robots ◽  
Uv C ◽  
Uvc Radiation

Sanitization with human efforts is not an easy task. Chances of contracting infections increases which leads to additional spread of bacteria. Currently, normal cleaning robots are used in most of the places but looking at the current situation the sanitization techniques need to be improved. The robot uses radiation of UV rays to kill the microrganisms. It gives a live video streaming of its surrounding using a Wi-fi based camera. With the help of Bluetooth module and android mobile, we can control the movement of the robot inside the room without being physically present. It is built with PIC Microcontroller and Ultraviolet-C (UVC) Sanitization LED. UV-C has bandwidth range of 200-280nm and is most powerful when it comes to killing pathogens in the room. This allows us to sterilise the room effectively. By killing the germs, the UV light restricts their multiplication by destroying their reproductive system. Thus use of this robot lowers the threat of infection, cost of traditional cleaning and sterilisation and increases security in medical facilities. Thus, we are trying to implement a more efficient way of sanitization by building a Low cost UV sanitization Robot which can be used in small clinics and for household purpose.

Enhanced ofloxacin degradation efficiency on porous CeTi2O6 photocatalyst-CTAB induced porosity

2020 ◽  
Vol 16 ◽  
Author(s):  
Lili Yang ◽  
Chuanguo Li ◽  
Wenjie Zhang
Keyword(s):  
Electron Microscopy ◽  
Porous Structure ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Organic Pollutants ◽  
Photoelectron Spectroscopy ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Light Illumination ◽  
X Ray

BACKGROUND: Photocatalytic oxidation of organic pollutants in the environment has been studied for more than half a century. Titanate has the activity on degradation of organic pollutants under UV light illumination. Template directed sol-gel method is capable of producing porous structure in titanate during high temperature thermal treatment. METHODS: The materials were characterized using X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, surface area and pore size analyses, UV-Visible spectrometry, and X-ray photoelectron spectroscopy. Photocatalytic activity of the CeTi2O6 material was evaluated through ofloxacin degradation. RESULTS: Brannerite structured CeTi2O6 was the major component in the samples, and the addition of CTAB caused a slight growth of CeTi2O6 crystals. Porous structure formed in the porous sample after the removal of CTAB template, and the surface area and pore volume were greatly enlarged. The first order reaction rate constant for photocatalytic degradation of ofloxacin was 9.60×10-3 min-1 on the nonporous CeTi2O6 sample, and it was as large as 2.44×10-2 min-1 on the porous CeTi2O6 sample. The addition of CTAB can influence the physico-chemical properties of the porous CeTi2O6, such as the improved activity on photocatalytic degradation of ofloxacin. CONCLUSION: The CeTi2O6 samples were composed of majority brannerite CeTi2O6, and CeTi2O6 crystallite sizes for the nonporous and porous samples were 38.1 and 43.2 nm. The burning up of CTAB during calcination produced abundant pores in the porous material. After 50 min of reaction, photocatalytic degradation efficiencies on the nonporous and porous CeTi2O6 samples were 38.1% and 70.5%.

Understanding the effect of ultraviolet light intensity on disinfection performance through the use of ultraviolet measurements and simulation

2018 ◽  
Vol 39 (9) ◽  
pp. 1122-1124 ◽  
Author(s):  
Brian M. Tande ◽  
Todd A. Pringle ◽  
William A. Rutala ◽  
Maria F. Gergen ◽  
David J. Weber
Keyword(s):  
Clostridium Difficile ◽  
Light Intensity ◽  
Ultraviolet Light ◽  
Computer Simulations ◽  
Uv Light ◽  
Ultraviolet C ◽  
Uv C

AbstractWe measured the disinfection of MRSA and Clostridium difficile spores using an ultraviolet C (UV-C) device, and we correlated those results to measurements and computer simulations of UV-C surface intensity. The results demonstrate both large differences in UV light intensity across various surfaces and how this leads to significant differences in disinfection.

scholarly journals Efficient and Rapid Photocatalytic Degradation of Methyl Orange Dye Using Al/ZnO Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1059
Author(s):  
Piangjai Peerakiatkhajohn ◽  
Teera Butburee ◽  
Jung-Hoon Sul ◽  
Supphasin Thaweesak ◽  
Jung-Ho Yun
Keyword(s):  
Methyl Orange ◽  
Photocatalytic Degradation ◽  
Removal Efficiency ◽  
Zno Nanoparticles ◽  
Light Absorption ◽  
Uv Light ◽  
Light Irradiation ◽  
Zno Nps ◽  
Calcination Temperatures ◽  
Degradation Of Methyl Orange

ZnO and Aluminum doped ZnO nanoparticles (Al/ZnO NPs) were successfully synthesized by the sol-gel method. Together with the effect of calcination temperatures (200, 300 and 400 °C) and Al dosage (1%, 3%, 5% and 10%) on structural, morphological and optical properties of Al/ZnO NPs, their photocatalytic degradation of methyl orange (MO) dye was investigated. The calcination temperatures at 200, 300 and 400 °C in forming structure of ZnO NPs led to spherical nanoparticle, nanorod and nanoflake structures with a well-crystalline hexagonal wurtzite, respectively. The ZnO NPs calcined at 200 °C exhibited the highest specific surface area and light absorption property, leading to the MO removal efficiency of 80% after 4 h under the Ultraviolet (UV) light irradiation. The MO removal efficiency was approximately two times higher than the nanoparticles calcined at 400 °C. Furthermore, the 5% Al/ZnO NPs exhibited superior MO removal efficiency of 99% in only 40 min which was approximately 20 times enhancement in photocatalytic activity compared to pristine ZnO under the visible light irradiation. This high degradation performance was attributed to the extended light absorption, narrowed band gap and effective suppression of electron–hole recombination through an addition of Al metal.

Optimization of Process Parameters for the Photocatalytic Degradation of 2,4-Dichlorophenol in Aqueous Solutions

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Sushil Kumar Kansal ◽  
Manohar Singh ◽  
Dhiraj Sud
Keyword(s):  
Response Surface Methodology ◽  
Photocatalytic Degradation ◽  
Sodium Hypochlorite ◽  
Uv Light ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Operational Parameters ◽  
Optimization Of Process Parameters ◽  
Oxidant Concentration ◽  
Optimal Values

In the present study, the photocatalytic degradation of 2,4-DCP has been investigated in a batch reactor under UV light in slurry mode using titania P-25 (surface area 50 m2/g) as a photocatalyst and sodium hypochlorite as an oxidant. Variables studied include catalyst dose, pH and oxidant concentration. The rate of degradation was studied in terms of changes in concentration of the pollutant and reduction in chemical oxygen demand. The optimal values of operational parameters leading to 2,4-DCP abatement were obtained by using response surface methodology.

scholarly journals Responses of Periphyton Microbial Growth, Activity, and Pollutant Removal Efficiency to Cu Exposure

2020 ◽  
Vol 17 (3) ◽  
pp. 941
Author(s):  
Wei Zhong ◽  
Weiqun Zhao ◽  
Jianhui Song
Keyword(s):  
Removal Efficiency ◽  
Microbial Growth ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Carbon Source Utilization ◽  
Functional Responses ◽  
Growth Activity ◽  
Underlying Mechanisms ◽  
Microbial Metabolic Activity ◽  
Pollutant Removal Efficiency

Periphyton is an effective matrix for the removal of pollutants in wastewater and has been considered a promising method of bioremediation. However, it still needs to be verified whether periphyton can maintain microbial activity and pollutant removal efficiency when dealing with the influence with complex components, and the underlying mechanisms of periphyton need to be revealed further. Herein, this study investigated the microbial growth, activity and functional responses of periphyton after removal of Cu from wastewater. Results showed that the cultivated periphyton was dominated by filamentous algae, and high Cu removal efficiencies by periphyton were obtained after 108 h treatments. Although 2 mg/L Cu2+ changed the microalgal growth (decreasing the contents of total chlorophyll-a (Chla), the carbon source utilization and microbial metabolic activity in periphyton were not significantly affected and even increased by 2 mg/L Cu2+. Moreover, chemical oxygen demand (COD) removal rates were sustained after 0.5 and 2 mg/L Cu2+ treatments. Our work showed that periphyton had strong tolerance and resistance on Cu stress and is environmentally friendly in dealing with wastewater containing heavy metals, as the microbial functions in pollutant removal could be maintained.

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