Addition Of Activated Carbon Research Articles

Effect of honeycomb, granular, and powder activated carbon additives on continuous lactic acid fermentation of complex food waste with mixed inoculation

To accelerate and stabilize lactic acid fermentation from food waste, three types of activated carbon, including honeycomb activated carbon, granular activated carbon, and powder activated carbon, were tested as additives in continuous food waste fermentation processes. The results showed that carbohydrate was the primary substrate for lactic acid production, but its conversion reached a high, stable level after a long period of microbial acclimation in the control system. Activated carbon, especially honeycomb activated carbon accelerated the stabilization of lactic acid fermentation and enhanced the tolerance of fermentation systems to a hostile and fluctuating environment. The addition of activated carbon increased the oxidation-reduction potential to approximately 100mV and altered the microbial communities. Homolactic fermentation bacteria were dominant in all the systems, and the honeycomb activated carbon addition stimulated the growth of unclassified Lactobacillus and immobilized Lactobacillus panis with strong carbohydrate metabolism. In addition, powder activated carbon enhanced the degradation of protein due to the multiplying Pseudomonas. At the stable stage, the organic conversion rates were close in the control system and the systems with the activated carbon addition, and the lactic acid concentrations in these systems remained at 8000-10,000mg/L. Considering the cost of the additives, honeycomb activated carbon is a good choice to stabilize lactic acid production from food waste.

Per- and polyfluoroalkyl substances (PFASs) in Swedish household dust and exposure of pet cats

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of products and have been found ubiquitously in our indoor environment, and there is evidence that exposure to PFAS can lead to adverse endocrine effects, such as thyroid hormone disruption. Pet cats have a high dust intake due to their grooming behavior and have been shown to be a suitable sentinel species for assessment of toddler’s exposure. Here we used paired household dust (n=46) and cat serum (n=27) samples to establish whether dust is a relevant exposure pathway to PFASs. An analytical method for PFAS analysis was optimized using a low volume of cat serum samples, combining solid-phase extraction and online sample cleanup. Dust was extracted with methanol by sonication and cleaned up by addition of active carbon. In total, 27 PFASs were analyzed by liquid chromatography/mass spectrometry analysis. The correlation between PFAS levels in dust and serum, serum lipids and thyroid hormone levels, and PFAS levels in dust between different rooms were statistically evaluated. PFOS and PFDA could be quantified in all cat serum samples (median 2300 pg/mL and 430 pg/mL, respectively), followed by PFOA (median 1100 pg/mL), quantified in 96% of the samples. The levels of 6:2 and 8:2 diPAPs were determined in 65% and 92% of the serum samples, respectively, and were an order of magnitude lower (1.4–160 pg/mL). Household dust on the other hand was dominated by 6:2 and 8:2 diPAPs, with a median of 65 ng/g dust and 49 ng/g dust, respectively. PFOS (median 13 ng/g dust) and PFOA (median 9 ng/g dust) were quantified in 93% of the dust samples. Only eight PFASs were detected (>LOD) in at least 50% of the samples of both matrices and could be paired. Significant correlations between cat serum and dust were found for PFOA (rS=0.32, p<0.049) and PFUnDA (rS=0.55, p<0.001). Significant positive correlations were found between serum total thyroxine (rS=0.11, p<0.05) and PFNA and between serum cholesterol and PFHpA (rS=0.46, p<0.01), PFUnDA (rS=0.40, p<0.05), PFDoDA (rS=0.44, p<0.01), and sum PFAS (rS=0.48, p<0.01). In conclusion, this study confirmed that dust is a relevant exposure pathway for the ingestion of some PFASs for cats, and the serum levels of PFASs could be of relevance for the cat’s health.

MBR공정에 있어서 GAC가 분리막 오염에 미치는 영향

MBR공정에 있어서 GAC가 분리막 오염에 미치는 영향

Enhanced cementation of Cd2+, Co2+, Ni2+, and Zn2+ on Al from sulfate solutions by activated carbon addition

Cadmium (Cd), cobalt (Co), nickel (Ni), and zinc (Zn) are important components of batteries and renewable energy technologies but their recovery from pregnant leach solutions or removal from polluted soil systems and water bodies remain challenging. In this study, we report the removal/recovery of heavy metal ions (Cd2+, Co2+ and Ni2+, and Zn2+) from sulfate solutions by a novel cementation technique using aluminum (Al) and activated carbon (AC) called “AC/Al-cementation”. The results showed ~0% removal/recovery efficiencies with Al only for the four heavy metals but with “AC/Al-cementation”, these values increased to 96%, 61%, 57%, and 45% for Zn2+, Ni2+, Co2+, and Cd2+, respectively. Detailed residue characterizations using SEM-EDX, XPS, and AES showed substantial deposition of heavy metal ions in their elemental forms, indicating that the primary mechanism of removal/recovery was cementation. Moreover, the results identified the critical role of AC as an electron pathway from Al (electron donor) to metal ions (electron acceptors) even though Al was covered with Al2O3. Finally, hydrogen overpotential and the subsequent passivation of cemented heavy metals by Al(OH)3 were important limiting factors and processes affecting the efficiency of “AC/Al-cementation” technique.

Effect of Activated Carbon Addition to Cheese Whey Wastewater Electrolysis via Microbial Electrolysis Cell

Effect of Activated Carbon Addition to Cheese Whey Wastewater Electrolysis via Microbial Electrolysis Cell

A comparative study on the efficiency of natural and synthetic coagulant for microalgal removal from the Nile water; effect of activated carbon addition

A looking for natural coagulants for algal removal is one of the researchers' interests due to synthetic coagulants concerning different health problems. So, in this study, a comparative investigation was performed to determine the effect of Alum, FeCl3 as synthetic coagulants, and Moringa seed extract as a natural coagulant. The synthetic coagulants were prepared and Moringa seed has been watered extracted; all coagulants performed by Jar test at different doses for algal removal, and the effect of adding the powder activated carbon (PAC) derived from cotton stalk was tested as a coagulant aid. The data revealed that all coagulants show good removal but the Moringa seed extract in addition to PAC exhibited the excellent result of removal reached 100%.

The effect of activated carbon additives on lead sulphide thin film for solar cell applications

A photovoltaic device with an efficiency that could break the theoretical limit, exceeding ~60% is the focus in the research field in recent years. The efficiency of three important processes in a photovoltaic device need to be ensured to materialize the goal i.e., electron excitations, injections and regenerations. A multiple exciton generation (MEG) mechanism has been proven to increase the photovoltaic conversion efficiency - achievable via usage of small size lead chalcogenides as main light absorber of the photovoltaic device. An efficient electron injection in an excitonic solar cell could be achieved upon fulfilment of the following factors i.e., (i) LUMOfluorophore>CBphotoelectrode, and (ii) small offset between the LUMOfluorophore and CBphotoelectrode. The opto-electronic properties of lead chalcogenide are tuneable based on its size and morphology. Therefore, a synthesis method that could control the size and morphology of the yielded lead chalcogenide plays an important role. This research investigated the effect of additional activated carbon (AC) to the yielded PbS using vacuum thermal evaporator method. The PbS thin films were fabricated with addition of AC with different surface areas i.e., 80 m2/g, 650 m2/g and 1560 m2/g using thermal evaporator at vacuum pressure of 1.0 × 10−5 Torr. The surface area of the ACs was determined using Micromeritics ASAP 2020 BET (Brunauer-Emmett-Teller). The morphology, elemental analysis, crystal structure, opto-electronic, electron injection efficiency and electrical conductivity of the PbS thin film was characterized using Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Spectrometer (EDX), X-Ray Diffractometer (XRD), absorption spectrometer, photoluminescence spectrometer (PL), and Bridge Technology 4-point probes (4PP) respectively. The excited and ground states of the PbS, and redox potential of ionLic PMII electrolyte were determined using quantum chemical calculations at b3lyp/lanl2dz level of theory. Three important observations have been made i.e., (i) addition of AC with the PbS reactants affects the yielded morphology of PbS thin film, (ii) bare PbS/TiO2 device structure offers electron injection efficiency as high as 97% from the PbS to TiO2, and (iii) the bare PbS/TiO2 device structure would offer maximum VOC of ca. 1.7 V, however need to be paired with an electrolyte that possess oxidation potential of ca. −6.5 eV.

Biochar and activated carbon enhance ethanol conversion and selectivity to caproic acid by Clostridium kluyveri

Syngas from biomass or steel mills can be fermented into a dilute stream of ethanol and acetic acid, which requires energy intensive distillation for product recovery. This can be circumvented by selective secondary fermentation of the syngas fermentation effluent to caproic acid as easier recoverable platform chemical with Clostridium kluyveri. Here, we explore the impact of biochar and activated carbon on this process. Changes during the fermentation with biochar or activated carbon were monitored, different doses were tested and the recyclability of biochar and activated carbon was assessed. Biochar decreased the lag phase and increased the caproic acid production rate (up to 0.50 g·L-1·h-1). Upon recycling for subsequent fermentation, biochar retained this property largely. Activated carbon addition, especially at high dose, could potentially increase the conversion and selectivity towards caproic acid to 14.15 g·L-1 (control: 11.01 g·L-1) and 92% (control: 84%), respectively.

Insight into sludge anaerobic digestion with granular activated carbon addition: Methanogenic acceleration and methane reduction relief

In this study, the multiple effects of granular activated carbon (GAC) on sludge anaerobic digestion at ambient (16–24 °C), mesophilic (35 °C) and thermophilic (55 °C) temperature were investigated. After GAC addition, although the methane yields of raw sludge were reduced by 6.5%–36.9%, the lag phases of methanogenesis were shortened by 19.3%–30.6% and the reductions of methane yields were declined to only 5.9%–8.1% simultaneously for pretreated sludge. The inhibitory substances like phenols that generated by thermal pretreatment were reduced after GAC addition, which were demonstrated to be responsible for the methanogenic acceleration. Meanwhile, the methane reduction due to the non-selective adsorption by GAC could be mitigated by pretreatment and elevated temperature. Thus, a strategy coupling thermal pretreatment with detoxification by GAC was proposed to improve the methane production rate and avoid the negative effects during sludge anaerobic digestion with GAC addition.

Dentin Abrasivity and Cleaning Efficacy of Novel/Alternative Toothpastes.

To investigate dentin abrasivity and cleaning efficacy of novel/alternative toothpastes containing diamond particles, active carbon, sea salt or organic oils. Seventy-two bovine dentin samples (for measuring abrasivity) and 60 human dentin samples (for assessing cleaning efficacy) were used in this study. Samples were divided into six groups as follows: group 1: Elmex Kariesschutz (hydrated silica); group 2: Lavera Neutral Zahngel (sea salt); group 3: Curaprox Black is White (active carbon); group 4: Swiss Smile Diamond Glow (diamond powder); group 5: Ringana Fresh Tooth Oil (hydrated silica); and group 6: artificial saliva. Samples were brushed for a total of 26 min at 120 strokes/min, replacing slurries (1 part respective toothpaste and 2 parts artificial saliva) every 2 min. Finally, abrasive dentin wear was measured profilometrically and cleaning efficacy planimetrically. The highest abrasivity values were observed for Lavera Neutral Zahngel (sea salt 9.2 µm) and Elmex Kariesschutz group (hydrated silica 6.0 µm). The lowest abrasivity value was observed for Ringana Fresh Tooth Oil group (hydrated silica 1.3 µm). The highest cleaning efficacy was observed for Elmex Kariesschutz group (86.7%) and the lowest cleaning efficacy was observed for Ringana Fresh Tooth Oil group (31.3%). The addition of diamond powder or active carbon to toothpastes could offer high cleaning efficacy with low dentin abrasivity. The addition of sea salt to traditional abrasives might cause high abrasive dentin wear without adding further cleaning benefit.

Catalytic mechanism of activated carbon-assisted bioleaching of enargite concentrate

The catalytic mechanism of activated carbon-assisted bioleaching of enargite concentrate (enargite 37.4%; pyrite 47.3%) was investigated by employing microbiological, electrochemical and kinetic studies. By using moderately thermophilic microorganisms at 45 °C, the final Cu dissolution was improved from 36% to 53% at 0.2% (w/v) activated carbon. An excess activated carbon addition showed an adverse effect. The enargite mineral itself favored higher solution redox potential (Eh) for solubilization. However, the dissolution of co-existing pyrite, which also favors high Eh, immediately hindered enargite dissolution through the passivation effect. The surface of activated carbon functioned as an electron mediator to couple RISCs oxidation and Fe3+ reduction, so that elevation of the Eh level was controlled by offsetting microbial Fe3+ regeneration. As long as the Eh level was suppressed at <700 mV, the dissolution of pyrite was largely avoided, enabling a steady and continuous dissolution of the enargite mineral through the surface chemical reaction model. When the Eh-control by activated carbon becomes no longer sustainable and the Eh hits 700 mV, rapid pyrite dissolution was initiated and the surface chemical reaction of enargite dissolution came to an end. Arsenic species dissolved from enargite was constantly immobilized with an efficiency of 75–90% as amorphous ferric arsenate. However, the sudden initiation of pyrite dissolution also triggered the re-solubilization of ferric arsenate. Therefore, the sustainable Eh-controlling effect was shown to be critical to enable longer Cu dissolution from enargite as well as stabilization of As precipitates.

Activated carbon additives for technetium immobilization in bentonite-based engineered barriers for radioactive waste repositories

Safe disposal of nuclear waste in a geologic repository will rely on natural geologic features and engineered barriers to greatly retard the movement of radionuclides from the repository. Clay minerals including bentonite are effective in retarding the migration of many radionuclides, but are ineffective for anionic radionuclides, of which pertechnetate is of particular concern owing to its relatively long half-life and the lack of natural isotopes that dilute it. Activated carbon is proposed as an additive material for reducing pertechnetate mobility in the nearfield. Activated carbon materials of different origins quantitatively sorb pertechnetate from aqueous solution under oxidizing conditions during the first day of contact, and sequential extraction showed that 73 % of this technetium is in the strongly bound fraction. X-ray photoelectron spectra (XPS) and extended X-ray absorption fine structure (EXAFS) spectra both demonstrated that no reduction of technetium occurred in the studied systems. The interaction of technetium with a composite material consisting of bentonite and activated carbon was studied at the first time. Effective technetium sorption was shown, with distribution coefficients (Kd) up to 740 cm3. g−1.

Characterization of LTO/Silicon Oxycarbide with Activated Carbon Addition for Anode of Lithium-Ion Batteries

Lithium Titanate (LTO) is one of the anode materials that has good performance because of its unique properties, which is zero-strain. In this study, LTO was synthesized using the sol-gel method and mechanochemical hydrothermal with LiOH as the source of lithium-ion. Silicone oxycarbide (SiOC) is a ceramic material synthesized through a simple pyrolysis process of silicone oil precursors. Carbon used in this study is a carbon activated process so that activated carbon is obtained with a large pore size. The addition of activated carbon to the LTO is done during the sol-gel process, while the addition of SiOC to LTO-C is performed during the slurry making process. SEM-EDS shows the extent of the elements in the sample where Ti, F, Si, O, and C are present. Also, SEM-EDS characterization shows an increase in the amount of carbon in each sample. XRD shows the presence of the LTO spinel phase and impurity phases such as TiO2 rutile and anatase, and Li2TiO3. In EIS performance testing, low resistivity expresses high conductivity. In this research, high conductivity is owned by LTO-1% C/SiOC. In addition, CV and CD performance tests were performed where the highest specific capacity was obtained in the LTO-5%/SiOC samples.

Effects of activated carbon on mesophilic and thermophilic anaerobic digestion of food waste: Process performance and life cycle assessment

Anaerobic digestion (AD) is widely used to recover energy (in the form of methane) and nutrients (in the form of biofertilizer) from organic wastes, and adding conductive materials has been reported to be an effective way to enhance AD efficiency. However, the process performance and environmental sustainability of adding conductive materials into AD under different temperature conditions have not been addressed. In this study, four different groups of lab-scale reactors were operated under both mesophilic and thermophilic conditions and with/without activated carbon (AC) addition. Based on the lab-scale results, a pilot-scale reactor was used to highlight the effectiveness of activated carbon addition, and the derived data was used for a life cycle assessment (LCA) study. The results showed the enhancement of methane production by adding AC, particularly under thermophilic conditions. At the organic loading rate of 4.7 g VS/L/d, the average methane yield of the thermophilic AD reactors with AC was 550 mL CH4/g VS, which was significantly higher than that of the control reactors (i.e. 220 mL CH4/g VS). Adding AC into AD reactors accelerated the shift of dominant methanogenic pathways from aceticlastic methanogenesis to hydrogenotrophic methanogenesis by enriching Methanoculleus (84% of total archaea). The LCA results highlighted the environmental benefits of using activated carbon to enhance AD of food waste at both midpoint and endpoint levels based on ReCiPe2016 methodology.

Reduction of Organic Parameters in Apartment Wastewater using Sequencing Batch Reactor by adding Activated Carbon Powder

A Sequencing Batch Reactor (SBR) was used to reduce the concentration of organic parameters, that consisted of Chemical Oxygen Demand (COD), Total Nitrogen (N Total) and Total Suspended Solid (TSS) in an apartment wastewater, because the SBR system had a high space efficiency and was low in cost. The apartment wastewater was especially from the effluents of water closets and kitchen. In this study, we applied the SBR method and added activated carbon powder to treat apartment wastewater which had previously gone through the first settling process. This SBR was operated with various hydraulic retention times (HRT) which were 12, 24 and 36 hours respectively, and aeration rates of 3.5 and 7 L/min. Dissolved Oxygen (DO) testing was carried out at each stage of SBR, which aimed to measure and maintain stability at each stage of SBR. The results of the study were the optimum HRT and aeration rate, which were 36 hours and 7 L/min respectively. FTIR test was carried out to determine the efficiency of activated carbon addition in this SBR process. It was found that Activated Carbon increased SBR performance as evidenced by the COD removal rate reaching 89.5% and Total N 94.54%.

Treatment of municipal wastewater in AnMBRs with powdered activated carbon addition under psychrophilic temperatures.

The performance of anaerobic membrane bioreactors (AnMBRs) at psychrophilic temperatures commonly observed in temperate climates (10-24°C) was assessed. A unique aspect of the research was operation at controlled SRT with regular membrane cleaning. COD removal and permeate VFA concentrations were similar at 15 and 24°C and deteriorated at 10°C. As temperature decreased, the COD mass flow to methane decreased and COD mass flows in the permeate and waste sludge increased. At 24°C, rapid membrane TMP increases were not observed while at 15 and 10°C rapid increases occurred at 11.7±0.46 and 7.6±0.45days, respectively, indicating a greater fouling propensity of the mixed liquor at lower temperatures. When the temperature was reduced from 15°C to 10°C in a transient test, CH4 production was reduced and VFA concentrations increased. A 2-3 SRT lag in the responses suggested that the delayed response was due to long-term changes in microbial population. The permeate VFA content in a PAC-dosed reactor was lower than that without PAC dosing, and PAC addition increased the time to rapid TMP development to 11.3±0.46days from 7.4±0.49days. The primary benefit of PAC addition at low temperatures is enhanced membrane performance. PRACTITIONER POINTS: AnMBRs can produce high-quality effluents at temperatures of 15°C Membrane fouling increases as temperature decreases Bioreactor performance was sustained for 2-3 SRTs after temperature decrease PAC addition reduced the permeate VFA concentrations Membrane fouling at 10°C was reduced through PAC addition.

A Study on CO2 and NH3 Reduction during Composting of Chicken Manure by Activated Carbon Addition

A Study on CO₂ and NH₃ Reduction during Composting of Chicken Manure by Activated Carbon Addition

Durability of fiber boards made of jabon and andong bamboo with additional activated carbon additives against dry wood termites and subterranean termites

Utilization of wood waste as material to produce medium density fiber-board (MDF) will help to reduce the rate of deforestation. Jabon waste (Anthocephalus cadamba Miq.) combined with andong (Gigantochloa pseudoarundinacea (Steudel) Widjaja) bamboo waste with 50%:50% ratio were made into MDF with the size of 30 cm x 30 cm x 1.2 cm and density 0.45 kg/m3 and 0.55 kg/m3. Activated carbon additive 4% were then added in the process. MDF durability test towards attack from Cryptotermes cynocephalus Light dry wood termite and Coptotermes curvignathus Holmgrem subterranean termites were done according to SNI 01-7207-2014. Result shows that the addition of activated carbon powder increased the MDF’s dry wood termites-durability level from IV (not-durable) to III (moderately durable). Meanwhile, adding activated carbon powder additive in MDF had not increase its durability to subterranean termites attack. The MDF durability level against soil termite stood at the same level of IV (not-durable). Improvement needs to be done for MDF made of jabon and andong bamboo mix using preservatives to increase the MDF durability level.

Influence of activated carbon on performance and microbial communities in the treatment of solvent pollutant mixtures in a continuous stirred tank reactor

Granular activated carbon addition could promote specific microorganisms which favour the anaerobic removal of non-readily biodegradable solvent compounds through their influence on the degradation (methanogenesis) of intermediates.

The Effect of Activated Carbon Addition on Woody Cutting Waste Briquette Combustion Quality

This study aims to increase the calorific value of woody cutting waste briquette by adding activated carbon. The previous experiments showed that the highest calorific value of woody cutting waste briquette reached only 3 630 kCal kg–1. In this research, activated carbon was made of Palmyra palm fiber using H3PO4as an activator solvent. There are four different proportion of activated carbon used in the experiment, for example, 5 %, 10 %, 15 %, and 20 % with 10 % tapioca flour binder. The woody cutting waste were carbonized and sieved into 50 mesh to 100 mesh. The briquette performance was tested using proximate analysis, bomb calorimeter, and combustion analysis. The addition of activated carbon in briquette could increase the calorific value from 3 630 kCal kg–1to around 4 500 kCal kg–1.