scholarly journals Performance of a granular activated carbon biologically active filter (GAC-BAF) for removing microcystin-LR (MC-LR) from eutrophic water

2020 ◽  
Author(s):  
Wei Xu ◽  
Meijun Kong ◽  
Jie Song ◽  
Zhen Zhang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Indirect Evidence ◽  
Granular Activated Carbon ◽  
Active Filter ◽  
Superficial Velocity ◽  
Biologically Active ◽  
Column Height ◽  
Higher Temperature ◽  
Lower Temperature

Abstract Microcystin-LR (MC-LR) removals linked with empty bed contact time (EBCT), temperature and backwash strategies are important for biologically active filter (BAF) application but remain not entirely clear. In addition, there is still a lack of understanding about the bio-regeneration of MC-LR adsorption capacity in a BAF. This study examined MC-LR removals by a granular activated carbon-biologically active filter (GAC-BAF) as a function of EBCT, temperature, and backwash strategies. Results demonstrated that the optimum EBCT (1.2 h for this study) likely depended upon an optimum superficial velocity as well as the GAC column height. A superficial velocity not greater than 0.5 m/h was deemed appropriate according to this research. The MC-LR removals achieved at the optimum EBCT reached 54.8%–72.0%. A higher temperature resulted in a greater MC-LR removal; adsorption might contribute to effective MC-LR removal by the GAC-BAF at a lower temperature. A strategy (Air + air-water + water) was suggested as an optimal backwash strategy for GAC-BAFs in terms of MC-LR removal. A comparison of the effectiveness of the experimental GAC-BAF in continuous and discontinuous operations on MC-LR removals was conducted, from which indirect evidence for bio-regeneration of MC-LR adsorption capacity of the GAC was obtained.

scholarly journals Removal of Heavy Metal Ion Using Polymer-Functionalized Activated Carbon: Aspects of Environmental Economic and Chemistry Education

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Hoang Thu Ha ◽  
Nguyen Thi Huong ◽  
Le Linh Dan ◽  
Nguyen Duy Tung ◽  
Vinh Bao Trung ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Metal Ion ◽  
Chemistry Education ◽  
Atomic Radius ◽  
Toxic Heavy Metals ◽  
Pure Nitrogen ◽  
Amine Functionalized ◽  
Higher Temperature ◽  
Lower Temperature

Numerous countries have shown signs of environmental pollution to prioritize economic growth and benefits, leading to seriously contaminated waters. This work indicated the method to synthesize a green material, which could remove contaminants to protect the natural environment. The porosity and functionality effects of amine-functionalized activated carbon (AFAC) enhanced the removal of toxic heavy metals (THMs) in aqueous solution. The raw activated carbon (RAC) was thermally modified with ultrahigh pure nitrogen (UHPN) at 500°C and 1000°C and then amine-functionalized with coupling agent of aminopropyltriethoxysilane (APS). They were denoted as AFAC-5 and AFAC-10, respectively. The data showed an enhanced metal adsorption capacity of the AFACs, because the modification produced more desired porosity and increased amine functional groups. AFAC-10, modified at a higher temperature, showed much higher THM adsorption capacity than AFAC-5, modified at a lower temperature, and RAC. The adsorption capacity decreased in the following order: Ni > Cd > Zn, which was in good agreement with the increasing electronegativity and ionic potential and the decreasing atomic radius. The maximum THM adsorption capacity of AFAC-10 for Ni, Cd, and Zn was 242.5, 226.9, and 204.3 mg/g, respectively.

scholarly journals Electroadsorption of Bromide from Natural Water in Granular Activated Carbon

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 598
Author(s):  
David Ribes ◽  
Emilia Morallón ◽  
Diego Cazorla-Amorós ◽  
Francisco Osorio ◽  
María J. García-Ruiz
Keyword(s):  
Activated Carbon ◽  
Electric Field ◽  
Adsorption Capacity ◽  
Natural Water ◽  
Granular Activated Carbon ◽  
Open Circuit ◽  
Filter Press ◽  
Anodic Treatment ◽  
Positive Polarization ◽  
Two Stages

The adsorption and electroadsorption of bromide from natural water has been studied in a filter-press electrochemical cell using a commercial granular activated carbon as the adsorbent. During electroadsorption experiments, different voltages were applied (2 V, 3 V and 4 V) under anodic conditions. The presence of the electric field improves the adsorption capacity of the activated carbon. The decrease in bromide concentration observed at high potentials (3 V or 4 V) may be due to the electrochemical transformation of bromide to Br2. The anodic treatment produces a higher decrease in the concentration of bromide in the case of cathodic electroadsorption. Moreover, in this anodic electroadsorption, if the system is again put under open circuit conditions, no desorption of the bromide is produced. In the case of anodic treatment in the following adsorption process after 24 h of treatment at 3 V, a new decrease in the bromide concentration is observed as a consequence of the decrease in bromide concentration after the electrochemical stage. It can be concluded that the electroadsorption process is effective against the elimination of bromide and total bromine in water, with a content of 345 and 470 µg L−1, respectively, reaching elimination values of 46% in a single-stage electroadsorption process in bromide and total bromine. The application of the electric field to the activated carbon with a positive polarization (anodic electroadsorption) increases the adsorption capacity of the activated carbon significantly, achieving a reduction of up to 220 µg L−1 after 1 h of contact with water. The two stage process in which a previous electrochemical oxidation is incorporated before the electroadsorption stage significantly increased the efficiency from 46% in a single electroadsorption step at 3 V, to 59% in two stages.

Application of Carbonaceous Materials to Phenol Removal from Aqueous Solution by Adsorption

2012 ◽  
Vol 164 ◽  
pp. 297-301 ◽  
Author(s):  
Wei Fang Dong ◽  
Li Hua Zang ◽  
Qing Chao Gong ◽  
Cun Cun Chen ◽  
Cai Hong Zheng ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Petroleum Coke ◽  
Granular Activated Carbon ◽  
Powdered Activated Carbon ◽  
Maximum Adsorption Capacity ◽  
Phenol Removal ◽  
Carbonaceous Materials ◽  
Solution Ph ◽  
Equilibrium Studies

Low cost carbonaceous materials were evaluated for their ability to remove phenol from wastewater. The effects of adsorbents dosage, contact time and maximum adsorption capacity were investigated for granular activated carbon, powdered activated carbon, petroleum coke and multi-walled carbon nanotube (MWNT). Equilibrium studies were conducted in 50mg/L initial phenol concentration, solution pH of 5 and at temperature of 23°C. The results showed the adsorption process was fast and it reached equilibrium in 3 h. Petroleum coke and MWNT had poor adsorption which could reach the removal efficiency of phenol with 43.18% and 36.64% respectively. The granular activated carbon possessed good adsorption ability to phenol with 96.40% at the optimum dosage 5g and optimum time 90min.The powdered activated carbon was an effective adsorbent with a maximum adsorption capacity of 42.32 mg/g.

scholarly journals The Bacterial Communities of Full-Scale Biologically Active, Granular Activated Carbon Filters Are Stable and Diverse and Potentially Contain Novel Ammonia-Oxidizing Microorganisms

2015 ◽  
Vol 81 (19) ◽  
pp. 6864-6872 ◽  
Author(s):  
Timothy M. LaPara ◽  
Katheryn Hope Wilkinson ◽  
Jacqueline M. Strait ◽  
Raymond M. Hozalski ◽  
Michael J. Sadowksy ◽  
...  
Keyword(s):  
Activated Carbon ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Bacterial Communities ◽  
Granular Activated Carbon ◽  
Full Scale ◽  
Biologically Active ◽  
Rrna Gene ◽  
Ammonia Oxidizing Bacteria ◽  
Content Type

ABSTRACTThe bacterial community composition of the full-scale biologically active, granular activated carbon (BAC) filters operated at the St. Paul Regional Water Services (SPRWS) was investigated using Illumina MiSeq analysis of PCR-amplified 16S rRNA gene fragments. These bacterial communities were consistently diverse (Shannon index, >4.4; richness estimates, >1,500 unique operational taxonomic units [OTUs]) throughout the duration of the 12-month study period. In addition, only modest shifts in the quantities of individual bacterial populations were observed; of the 15 most prominent OTUs, the most highly variable population (aVariovoraxsp.) modulated less than 13-fold over time and less than 8-fold from filter to filter. The most prominent population in the profiles was aNitrospirasp., representing 13 to 21% of the community. Interestingly, very few of the known ammonia-oxidizing bacteria (AOB; <0.07%) and no ammonia-oxidizingArchaeawere detected in the profiles. Quantitative PCR ofamoAgenes, however, suggested that AOB were prominent in the bacterial communities (amoA/16S rRNA gene ratio, 1 to 10%). We conclude, therefore, that the BAC filters at the SPRWS potentially contained significant numbers of unidentified and novel ammonia-oxidizing microorganisms that possessamoAgenes similar to those of previously described AOB.

Experimental validation of a test to estimate the remaining adsorption capacity of granular activated carbon for taste and odour compounds

2019 ◽  
Vol 5 (3) ◽  
pp. 609-617 ◽  
Author(s):  
Yifeng Huang ◽  
Zhijie Nie ◽  
Jie Yuan ◽  
Audrey Murray ◽  
Yi Li ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Water Treatment ◽  
Adsorption Capacity ◽  
Experimental Validation ◽  
Drinking Water Treatment ◽  
Granular Activated Carbon ◽  
Adsorptive Capacity

A test was developed to measure the present-day adsorptive capacity of granular activated to help drinking water treatment professionals to determine when the GAC needs replacement.

scholarly journals Efficient two-frequency ultrasound extraction of β-carotene from the fungus Blakeslea trispora

2017 ◽  
Vol 71 (4) ◽  
pp. 329-336 ◽  
Author(s):  
Anatoly Avdeenko ◽  
Elena Belova ◽  
Predrag Dasic ◽  
Svetlana Konovalova ◽  
Larisa Baklanova ◽  
...  
Keyword(s):  
Extraction Process ◽  
Extraction Methods ◽  
Biologically Active ◽  
Blakeslea Trispora ◽  
Concentration Gradients ◽  
Efficient Energy Transfer ◽  
Temperature Application ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Frequency Ultrasound

Carotenoids are known for their lower environmental pollution, lower costs, shorter extraction time compared to regular extraction methods and higher extraction efficiency. Ultrasound has significant advantages in the extraction of a great number of biologically active compounds including carotenoids. Benefits of using ultrasound for extraction of various compounds are numerous and include effective mixing and micro-mixing, more efficient energy transfer, reduced thermal and concentration gradients, reduced temperature. The aim of this work was to investigate the influence of two-frequency ultrasound main parameters such as ultrasonic intensity, sonication time, and temperature. Application of two-frequency ultrasound (simultaneous influence of ultrasound with frequency of 20?46 kHz, intensity of 1.5?2.5 W/cm2 and frequency of 1.0?2.0 MHz, intensity of 2.0?3.0 W/cm2) raises the percentage of ?-carotene extraction from biomass of the fungus Blakeslea trispora from 90?92% up to 98?99% in comparison with one frequency ultrasound. The recommended oil temperature for the extraction process is 35?C, because lower temperature leads to reduction of percentage of ?-carotene extraction, and higher temperature promotes unjustified increase of expenditure of energy.

Effects of molecular oxygen on GAC adsorption of energetics

1997 ◽  
Vol 35 (7) ◽  
pp. 197-204 ◽  
Author(s):  
Sarah L. VanderLoop ◽  
Makram T. Suidan ◽  
Sandra R. Berchtold ◽  
Moustafa A. Moteleb ◽  
Stephen W. Maloney
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Molecular Oxygen ◽  
Waste Treatment ◽  
Granular Activated Carbon ◽  
Adsorption Properties ◽  
Chemical Degradation ◽  
Degradation Reactions ◽  
Gac Adsorption

Munitions wastewaters are commonly treated by granular activated carbon (GAC) adsorption followed by incineration of the spent carbon. The design of effective GAC unit processes hinges on the knowledge of GAC adsorption capacity for the compounds of interest as well as the types of chemical interactions to expect. GAC can often catalyze polymerization or chemical degradation of the adsorbate in the presence of molecular oxygen. Some adsorbates, though less common, may be subject to catalytic activity even when no molecular oxygen is present. The products of these interactions may enhance or interfere with effective waste treatment. This study individually evaluated the adsorption properties of a variety of energetics compounds. A number of surface catalyzed polymerization and degradation reactions were noted.

Biodegradation and attenuation of MIB and 2,4-D in drinking water biologically active sand and activated carbon filters

2019 ◽  
Vol 5 (5) ◽  
pp. 849-860 ◽  
Author(s):  
Kyle K. Shimabuku ◽  
Thomas L. Zearley ◽  
Katherine S. Dowdell ◽  
R. Scott Summers
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Activated Carbon ◽  
Granular Activated Carbon ◽  
Biologically Active ◽  
Operational Conditions ◽  
Filter Performance ◽  
Contaminant Control ◽  
Variable Water ◽  
Trace Organic

Biologically acclimated sand and granular activated carbon (GAC) filter performance for trace organic contaminant control is compared under variable water quality and operational conditions.

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