scholarly journals Combined Electro-Fenton and Anodic Oxidation Processes at a Sub-Stoichiometric Titanium Oxide (Ti4O7) Ceramic Electrode for the Degradation of Tetracycline in Water

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2772
Author(s):  
Busisiwe N. Zwane ◽  
Benjamin O. Orimolade ◽  
Babatunde A. Koiki ◽  
Nonhlangabezo Mabuba ◽  
Chaimaa Gomri ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Anodic Oxidation ◽  
Removal Efficiency ◽  
Degradation Products ◽  
Complete Removal ◽  
Pollutant Removal ◽  
Carbon Felt ◽  
Oxidation Processes ◽  
Electrochemical Advanced Oxidation Processes ◽  
Total Organic Carbon Removal

The mineralization of tetracycline by electrochemical advanced oxidation processes (EAOPs) as well as the study of the toxicity of its intermediates and degradation products are presented. Electro-Fenton (EF), anodic oxidation (AO), and electro-Fenton coupled with anodic oxidation (EF/AO) were used to degrade tetracycline on carbon felt (cathode) and a sub-stoichiometric titanium oxide (Ti4O7) layer deposited on Ti (anode). As compared to EF and AO, the coupled EF/AO system resulted in the highest pollutant removal efficiencies: total organic carbon removal was 69 ± 1% and 68 ± 1%, at 20 ppm and 50 ppm of initial concentration of tetracycline, respectively. The effect of electrolysis current on removal efficiency, mineralization current efficiency, energy consumption, and solution toxicity of tetracycline mineralization were investigated for 20 ppm and 50 ppm tetracycline. The EF/AO process using a Ti4O7 anode and CF cathode provides low energy and high removal efficiency of tetracycline caused by the production of hydroxyl radicals both at the surface of the non-active Ti4O7 electrode and in solution by the electro-Fenton process at the cathodic carbon felt. Complete removal of tetracycline was observed from HPLC data after 30 min at optimized conditions of 120 mA and 210 mA for 20 ppm and 50 ppm tetracycline concentrations. Degradation products were elucidated, and the toxicity of the products were measured with luminescence using Microtox® bacteria toxicity test.

scholarly journals Electro-Fenton for Industrial Wastewater Treatment: A Review

2019 ◽  
Vol 125 ◽  
pp. 03003
Author(s):  
Elin Marlina ◽  
Purwanto
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Advanced Oxidation Processes ◽  
Pollutant Removal ◽  
Operating Parameters ◽  
Fenton Process ◽  
Phenol Compounds ◽  
Oxidation Processes ◽  
Electrochemical Advanced Oxidation Processes ◽  
Recent Developments

Electro-Fenton is part of electrochemical advanced oxidation processes (EAOPs) which have been widely used to treat various types of waste such as color, drugs, phenol compounds, leachate, surfactants, and others. This article focuses on the effects of various operating parameters and recent developments in the electro-Fenton process, and then their optimum ranges for maximum pollutant removal and various pollutants removed by this process is observed.

scholarly journals Heterogeneous Electro-Fenton-like Designs for the Disposal of 2-Phenylphenol from Water

2021 ◽  
Vol 11 (24) ◽  
pp. 12103
Author(s):  
Antía Fdez-Sanromán ◽  
Rocío Martinez-Treinta ◽  
Marta Pazos ◽  
Emilio Rosales ◽  
María Ángeles Sanromán
Keyword(s):  
Advanced Oxidation Processes ◽  
Heterogeneous Catalysts ◽  
Advanced Oxidation ◽  
Complete Removal ◽  
Order Kinetic ◽  
Carbon Felt ◽  
Oxidation Processes ◽  
First Order ◽  
Order Kinetic Model ◽  
Radical Generation

The hunt for efficient and environmentally friendly degradation processes has positioned the heterogeneous advanced oxidation processes as an alternative more interesting and economical rather than homogenous processes. Hence, the current study lies in investigating the efficiency of different heterogeneous catalysts using transition metals in order to prevent the generation of iron sludge and to extend the catalogue of possible catalysts to be used in advanced oxidation processes. In this study, nickel and zinc were tested and the ability for radical-generation degradation capacity of both ions as homogeneous was evaluated in the electro-Fenton-like degradation of 2-phenylphenol. In both cases, the degradation profiles followed a first-order kinetic model with the highest degradation rate for nickel (1 mM) with 2-phenylphenol removal level of 90.12% and a total organic reduction near 70% in 2 h. To synthesise the heterogeneous nickel catalyst, this transition metal was fixed on perlite by hydrothermal treatment and in a biochar or carbon nanofibers by adsorption. From the removal results using the three synthesized catalysts, it is concluded that the best catalysts were obtained by inclusion of nickel on biochar or nanofibers achieving in both with removal around 80% before 1 h. Thus, to synthetize a nickel electrocatalyst, nickel doped nanofibers were included on carbon felt. To do this, the amount of carbon black, nickel nanofibers and polytetrafluoroethylene to add on the carbon felt was optimized by Taguchi design. The obtained results revealed that under the optimised conditions, a near-complete removal was achieved after 2 h with high stability of the nickel electrocatalyst that open the applicability of this heterogeneous system to operate in flow systems.

scholarly journals Inorganic Nitrogen Production and Removal along the Sediment Gradient of a Stormwater Infiltration Basin

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 320
Author(s):  
Qianyao Si ◽  
Mary G. Lusk ◽  
Patrick W. Inglett
Keyword(s):  
Removal Efficiency ◽  
N Mineralization ◽  
Inorganic Nitrogen ◽  
Dry Season ◽  
Pollutant Removal ◽  
Net N Mineralization ◽  
Wet Season ◽  
Inorganic N ◽  
N Removal ◽  
Stormwater Infiltration

Stormwater infiltration basins (SIBs) are vegetated depressions that collect stormwater and allow it to infiltrate to underlying groundwater. Their pollutant removal efficiency is affected by the properties of the soils in which they are constructed. We assessed the soil nitrogen (N) cycle processes that produce and remove inorganic N in two urban SIBs, with the goal of further understanding the mechanisms that control N removal efficiency. We measured net N mineralization, nitrification, and potential denitrification in wet and dry seasons along a sedimentation gradient in two SIBs in the subtropical Tampa, Florida urban area. Net N mineralization was higher in the wet season than in the dry season; however, nitrification was higher in the dry season, providing a pool of highly mobile nitrate that would be susceptible to leaching during periodic dry season storms or with the onset of the following wet season. Denitrification decreased along the sediment gradient from the runoff inlet zone (up to 5.2 μg N/g h) to the outermost zone (up to 3.5 μg N/g h), providing significant spatial variation in inorganic N removal for the SIBs. Sediment accumulating around the inflow areas likely provided a carbon source, as well as maintained stable anaerobic conditions, which would enhance N removal.

scholarly journals Treatment of Combined Dairy and Domestic Wastewater with Constructed Wetland System in Sicily (Italy). Pollutant Removal Efficiency and Effect of Vegetation

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1086
Author(s):  
Mario Licata ◽  
Roberto Ruggeri ◽  
Nicolò Iacuzzi ◽  
Giuseppe Virga ◽  
Davide Farruggia ◽  
...  
Keyword(s):  
Plant Growth ◽  
Organic Compounds ◽  
Removal Efficiency ◽  
Constructed Wetland ◽  
Organic Pollutant ◽  
Dairy Farm ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Dairy Wastewater ◽  
Giant Reed

Dairy wastewater (DWW) contains large amounts of mineral and organic compounds, which can accumulate in soil and water causing serious environmental pollution. A constructed wetland (CW) is a sustainable technology for the treatment of DWW in small-medium sized farms. This paper reports a two-year study on the performance of a pilot-scale horizontal subsurface flow system for DWW treatment in Sicily (Italy). The CW system covered a total surface area of 100 m2 and treated approximately 6 m3 per day of wastewater produced by a small dairy farm, subsequent to biological treatment. Removal efficiency (RE) of the system was calculated. The biomass production of two emergent macrophytes was determined and the effect of plant growth on organic pollutant RE was recorded. All DWW parameters showed significant differences between inlet and outlet. For BOD5 and COD, RE values were 76.00% and 62.00%, respectively. RE for total nitrogen (50.70%) was lower than that of organic compounds. RE levels of microbiological parameters were found to be higher than 80.00%. Giant reed produced greater biomass than umbrella sedge. A seasonal variation in RE of organic pollutants was recorded due to plant growth rate Our findings highlight the efficient use of a CW system for DWW treatment in dairy-cattle farms.

Helminth eggs removal by microscreening for water reclamation and reuse

2008 ◽  
Vol 57 (5) ◽  
pp. 715-720 ◽  
Author(s):  
S. Quinzaños ◽  
C. Dahl ◽  
R. Strube ◽  
R. Mujeriego
Keyword(s):  
Pore Size ◽  
Removal Efficiency ◽  
Reclaimed Water ◽  
Quality Criteria ◽  
Complete Removal ◽  
Water Quality Criteria ◽  
Filter Cloth ◽  
Latex Particles ◽  
Helminth Eggs ◽  
Adverse Environmental Conditions

Irrigation with reclaimed water is becoming a practical alternative to conventional irrigation in semi-arid areas of the Mediterranean like Spain, but it requires a reliable treatment process to provide a safe water supply. Helminth eggs are one of the main concerns for the safe use of reclaimed water, as they can survive adverse environmental conditions and they are highly infective. Spanish water quality criteria and International guidelines set a limit of 0.1 eggs/l for water uses with unrestricted human exposure. Two microscreening processes have been tested to determine their potential for helminth eggs removal, after a conventional physic-chemical reclamation process. Hydrotech Drum and Discfilters®, provided with 10 μm pore size filter cloth, were tested to determine their efficiency for helminth eggs straining. An experimental test was conducted using 20 μm spherical latex particles, as surrogates for helminth eggs, to test the removal efficiency of a small full-scale drumfilter. In a subsequent laboratory test, actual Trichuris suis eggs were strained using a 10 μm pore size filter cloth from a discfilter. Results from both tests indicate that drum and discfilters are able to achieve 99% removal efficiency for spherical latex particles and a complete removal for helminth eggs in reclaimed water.

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 Aflatoxin removal of peanut meals with aqueous ethanol

1993 ◽  
Vol 50 (1) ◽  
pp. 154-156 ◽  
Author(s):  
H. Fonseca ◽  
M.A.B. Regitano-d'Arce
Keyword(s):  
Removal Efficiency ◽  
Extraction Efficiency ◽  
Aqueous Ethanol ◽  
Complete Removal ◽  
Oil Extraction ◽  
Anhydrous Ethanol ◽  
Minimum Amount ◽  
Residual Oil ◽  
Simultaneous Extraction

A preliminary approach to achieve compatible simultaneous extraction of aflatoxin and residual oil from pressed oil meals was conducted to determine the minimum amount of water to be added to ethanol versus necessary time to achieve complete removal of aflatoxin. Commercial anhydrous, 96, 93 and 90°GL ethanol were utilized in trials with Soxhlet extractors. Commercial anhydrous ethanol did not remove aflatoxin completely and the extraction efficiency in minutes was directly proportional to the amount of water present in the ethanol, as expected. Although 96°GL ethanol was efficient, alcoholic strengths between 96 and 99°GL need be evaluated to improve oil extraction, provided they do not decrease aflatoxin removal efficiency.

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