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Adu-Boahene F, Boakye P, Agyemang FO, Kanjua J, Oduro-Kwarteng S. Understanding fluoride adsorption from groundwater by alumina modified with alum using PHREEQC surface complexation model. Sci Rep 2023; 13:12307. [PMID: 37516751 PMCID: PMC10387067 DOI: 10.1038/s41598-023-38564-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 07/11/2023] [Indexed: 07/31/2023] Open
Abstract
Fluoride is recognized as a vital ion for human and animal growth because of the critical role it plays in preventing skeletal and dental problems. However, when it is ingested at a higher concentration it can cause demineralization of teeth and bones resulting in fluorosis, therefore, the production of high-adsorptive capacity material which is also cost-effective is necessary for the treatment of fluorides. In this study, aluminium foil is valorised into alumina nanoparticles. The as-prepared alumina was modified with alum in two different ratios of 1:0.5 and 1:1 (alumina to alum w/w%) and later used as adsorbents for the removal of fluoride from groundwater. The adsorbents were characterized by Fourier transform infrared spectroscopy, point of zero charge and X-ray diffraction. Different factors that influence the removal efficiency of fluorides such as pH, initial concentrations, contact time and adsorbent dosage were studied and optimized using a simulated fluoride solution. The optimum conditions obtained were used to test real groundwater. The static experiment conditions were used to calibrate a PHREEQC geochemical model which was later used to simulate the fluoride sorption onto the modified alumina at different conditions. PHREEQC was also coupled with parameter estimation software to determine equilibrium constants for the surface reactions between the fluoride species and the adsorbent in a way that the simulations accurately reflect the outcomes of laboratory experiments. Isotherm studies were carried out on the adsorbents. Both Langmuir and Freundlich's non-linear models fitted well for the equilibrium data. However, with a higher coefficient of regression and low chi-square test values, the adsorption process was more of chemisorption on a monolayer surface. Kinetic studies were also carried out by using the non-linear equations from the pseudo-first-order and pseudo-second-order models. The pseudo-second-order model fitted well for the equilibrium data. The mechanism for the fluoride ion adsorption was also studied by the intraparticle (IP) diffusion model and was found that IP was not the rate-determining factor, and therefore the most plausible mechanism for the sorption process was ion exchange or attraction of fluoride ions to the sorbent surface. The findings obtained from this research show that readily available aluminium waste could be valorised into a useful product that could be employed in the removal of fluoride from water samples, including groundwater, that may contain too much fluoride and pose a risk to the general public's health.
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Affiliation(s)
- Francis Adu-Boahene
- Department of Civil Engineering (Regional Water and Environmental Sanitation Centre, Kumasi), Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
| | - Patrick Boakye
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana.
- Institute of Computation and Neuroscience, Apemso, Kumasi, Ghana.
| | - Frank Ofori Agyemang
- Department of Materials Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
| | - Jolly Kanjua
- Institute of Computation and Neuroscience, Apemso, Kumasi, Ghana
| | - Sampson Oduro-Kwarteng
- Department of Civil Engineering (Regional Water and Environmental Sanitation Centre, Kumasi), Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
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Quansah AD, Dogbey F, Asilevi PJ, Boakye P, Darkwah L, Oduro-Kwarteng S, Sokama-Neuyam YA, Mensah P. Assessment of solar radiation resource from the NASA-POWER reanalysis products for tropical climates in Ghana towards clean energy application. Sci Rep 2022; 12:10684. [PMID: 35739146 PMCID: PMC9226134 DOI: 10.1038/s41598-022-14126-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/01/2022] [Indexed: 11/17/2022] Open
Abstract
In order to expand the output of solar power systems for efficient integration into the national grid, solar energy resource assessment at site is required. A major impediment however, is the widespread scarcity of radiometric measurements, which can be augmented by satellite observation. This paper assessed the suitability of satellite-based solar radiation resource retrieved from the NASA-POWER archives at \documentclass[12pt]{minimal}
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\begin{document}$$0.5^\circ \times 0.5^\circ$$\end{document}0.5∘×0.5∘ spatial resolution over Ghana–West Africa, to develop a long-term source reference. The assessment is based on the criteria of comparison with estimations from sunshine duration measurement for 22 synoptic stations. Overall, the satellite-based data compared well with ground-based estimations by r = 0.6–0.94 ± 0.1. Spatiotemporally, the agreement is strongest over the northern half Savannah-type climate during March–May, and weakest over the southern half Forest-type climate during June–August. The assessment provides empirical framework to support solar energy utilization in the sub-region.
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Affiliation(s)
- Alfred Dawson Quansah
- Research and Development Division, Ghana National Petroleum Corporation, Tema, Ghana.,Department of Mechanical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Felicia Dogbey
- Meteorology and Climate Science Unit, Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Prince Junior Asilevi
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Patrick Boakye
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Lawrence Darkwah
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Sampson Oduro-Kwarteng
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Yen Adams Sokama-Neuyam
- Department of Petroleum Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Patrick Mensah
- Department of Mechanical Engineering, Southern University and A&M College, Baton Rouge, LA, USA
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Pinto E, Aggrey WN, Boakye P, Amenuvor G, Sokama-Neuyam YA, Fokuo MK, Karimaie H, Sarkodie K, Adenutsi CD, Erzuah S, Rockson MAD. Cellulose processing from biomass and its derivatization into carboxymethylcellulose: A review. Scientific African 2022. [DOI: 10.1016/j.sciaf.2021.e01078] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Asilevi PJ, Boakye P, Oduro-Kwarteng S, Fei-Baffoe B, Sokama-Neuyam YA. Indoor air quality improvement and purification by atmospheric pressure Non-Thermal Plasma (NTP). Sci Rep 2021; 11:22830. [PMID: 34819562 PMCID: PMC8613239 DOI: 10.1038/s41598-021-02276-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 11/08/2021] [Indexed: 12/11/2022] Open
Abstract
Non-thermal plasma (NTP) is a promising technology for the improvement of indoor air quality (IAQ) by removing volatile organic compounds (VOCs) through advanced oxidation process (AOP). In this paper, authors developed a laboratory scale dielectric barrier discharge (DBD) reactor which generates atmospheric NTP to study the removal of low-concentration formaldehyde (HCHO), a typical indoor air VOC in the built environment associated with cancer and leukemia, under different processing conditions. Strong ionization NTP was generated between the DBD electrodes by a pulse power zero-voltage switching flyback transformer (ZVS-FBT), which caused ionization of air molecules leading to active species formation to convert HCHO into carbon dioxide (CO2) and water vapor (H2O). The impact of key electrical and physical processing parameters i.e. discharge power (P), initial concentration (Cin), flow rate (F), and relative humidity (RH) which affect the formaldehyde removal efficiency (ɳ) were studied to determine optimum conditions. Results show that, the correlation coefficient (R2) of removal efficiency dependence on the processing parameters follow the order R2 (F) = 0.99 > R2 (RH) = 0.96, > R2 (Cin) = 0.94 > R2 (P) = 0.93. The removal efficiency reached 99% under the optimum conditions of P = 0.6 W, Cin = 0.1 ppm, F = 0.2 m3/h, and RH = 65% with no secondary pollution. The study provided a theoretical and experimental basis for the application of DBD plasma for air purification in the built environment.
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Affiliation(s)
- Prince Junior Asilevi
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Patrick Boakye
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Sampson Oduro-Kwarteng
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Bernard Fei-Baffoe
- Department of Environmental Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Yen Adams Sokama-Neuyam
- Department of Petroleum Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
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Senanu BM, Boakye P, Oduro-Kwarteng S, Sewu DD, Awuah E, Obeng PA, Afful K. Inhibition of ammonia and hydrogen sulphide as faecal sludge odour control in dry sanitation toilet facilities using plant waste materials. Sci Rep 2021; 11:17803. [PMID: 34493737 PMCID: PMC8423729 DOI: 10.1038/s41598-021-97016-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/18/2021] [Indexed: 11/15/2022] Open
Abstract
On-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilets as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two dry sanitation facilities named T1 and T2. The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed that the odour levels for H2S in both T1 (3.17 ppm) and T2 (0.22 ppm) were above the threshold limit of 0.05 ppm, for unpleasantness in humans and vice versa for NH3 odour levels (T1 = 6.88 ppm; T2 = 3.16 ppm; threshold limit = 30 ppm limit). The biomasses exhibited low pH (acidic = 5–7) whereas the biochars and ashes had higher pHs (basic = 8–13). Basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%) than acidic biocovers. The effect of pH on suppression of NH3 was determined to be statistically insignificant at 95% confidence limit. In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that biochar produced from locally available waste plant-based materials, like sawdust, can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.
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Affiliation(s)
- Bernice Mawumenyo Senanu
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, PMB, UPO, Kumasi, Ghana
| | - Patrick Boakye
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, PMB, UPO, Kumasi, Ghana.
| | - Sampson Oduro-Kwarteng
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, PMB, UPO, Kumasi, Ghana.
| | - Divine Damertey Sewu
- Life Green Technology Co. Ltd., 875 Yuseong-daero, Yuseong-gu, Daejeon, 34158, Republic of Korea.,Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon, 34158, Republic of Korea
| | - Esi Awuah
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, PMB, UPO, Kumasi, Ghana
| | - Peter Appiah Obeng
- Department of Water and Sanitation, University of Cape Coast, Cape Coast, Ghana
| | - Kobina Afful
- Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, PMB, UPO, Kumasi, Ghana
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Sokama-Neuyam YA, Boakye P, Aggrey WN, Obeng NO, Adu-Boahene F, Woo SH, Ursin JR. Theoretical Modeling of the Impact of Salt Precipitation on CO 2 Storage Potential in Fractured Saline Reservoirs. ACS Omega 2020; 5:14776-14785. [PMID: 32596615 PMCID: PMC7315589 DOI: 10.1021/acsomega.0c01687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
Deep saline reservoirs have the capacity to hold large volumes of CO2. However, apart from the high brine salinity, which poses an injectivity challenge, a high percentage of saline reservoirs are also fractured. The mechanisms of drying and salt precipitation and the resulting impact on CO2 injection are unique in fractured reservoirs. Analytical models were developed to investigate the impact of salt precipitation on CO2 injectivity and storage capacity. Two types of fractured saline reservoirs were considered: type I fractured reservoirs, where storage capacity and injectivity are contributed by only fractures, and type II fractured reservoirs, where both fractures and the adjacent rock matrix blocks contribute to CO2 storage and injectivity. We found that, depending on the initial brine salinity, salt precipitation could severely impair CO2 injectivity and reduce storage capacity. Salt precipitation had a fourfold impact on CO2 injectivity compared to storage capacity. Type I reservoirs with high irreducible brine saturation were less susceptible to salt clogging in the fractures. The results also suggest that fractures with rectangular aperture were less likely to be plugged by salt compared to elliptical fractures. Contrary to previous reports, some fractured deep saline reservoirs may not be suitable for CO2 storage. Generally, type II fractured reservoirs were found to be more suitable for CO2 storage in terms of susceptibility to salt clogging. The findings provide valuable understanding of the mechanisms and effect of drying and salt precipitation on CO2 storage potential, making a strong case for CO2 storage in naturally fractured deep saline reservoirs.
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Affiliation(s)
- Yen A Sokama-Neuyam
- Department of Petroleum Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi 00233, Ghana
| | - Patrick Boakye
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
| | - Wilberforce N Aggrey
- Department of Petroleum Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi 00233, Ghana
| | - Nicholas O Obeng
- Department of Petroleum Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi 00233, Ghana
| | - Francis Adu-Boahene
- Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, PMB, Kumasi, Ghana
| | - Seung Han Woo
- Department of Chemical and Biological Engineering, Hanbat National University San 16-1, Deokmyeong-dong, Yuseong-gu, Daejeon 34158, Republic of Korea
| | - Jann Rune Ursin
- Department of Energy and Petroleum Engineering, University of Stavanger, Stavanger 4036, Norway
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7
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Mensah M, Asiedu NY, Neba FA, Amaniampong PN, Boakye P, Addo A. Modeling, optimization and kinetic analysis of the hydrolysis process of waste cocoa pod husk to reducing sugars. SN Appl Sci 2020. [DOI: 10.1007/s42452-020-2966-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Boakye P, Tran HN, Lee DS, Woo SH. Effect of water washing pretreatment on property and adsorption capacity of macroalgae-derived biochar. J Environ Manage 2019; 233:165-174. [PMID: 30579004 DOI: 10.1016/j.jenvman.2018.12.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/04/2018] [Accepted: 12/09/2018] [Indexed: 05/22/2023]
Abstract
The effects of water washing pretreatment process on the property and adsorption capacity of biochar were investigated at different biochar/water ratios from 1:5 to 1:100 (w/v). Saccharina japonica macroalgae-derived biochars (B300, B450, and B600) were prepared at 300 °C, 450 °C, and 600 °C, respectively. The optimal biochar/water ratio was obtained at 1:10. The results indicated that the washing pretreatment can contribute to dramatically increasing the specific surface area of biochars, but slightly increasing their porosity. The washed biochars were carbonaceous microporous materials (67-80% micropore volume), with their specific surface area and porosity being B600 (543 m2/g and 86%), B450 (521 m2/g and 75%), and B300 (188 m2/g and 80%), respectively. The unwashed biochars exhibited a significantly higher ash content (59%-65%) than washed biochars (26%-35%). Equilibrium adsorption study demonstrated that the Langmuir maximum adsorption capacity (Qomax) of crystal violet cationic dye decreased in the following order: unwashed-B450 (1719 mg/g) > washed-B450 (1277 mg/g) > commercial activated carbon (492 mg/g). The washing pretreatment can remove solute-inorganic minerals to prevent their release from biochar during the dye adsorption. The washed biochar with its excellent adsorption capacity can serve as a highly sustainable and industrially viable adsorbent for the removal of cationic dyes from waste bodies.
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Affiliation(s)
- Patrick Boakye
- Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseodaero, Yuseong-gu, Daejeon, 34158, South Korea; Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology, UPO, Kumasi, Ghana
| | - Hai Nguyen Tran
- Institute of Research and Development, Duy Tan University, Da Nang, 550000, Vietnam
| | - Dae Sung Lee
- Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 41566, South Korea
| | - Seung Han Woo
- Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseodaero, Yuseong-gu, Daejeon, 34158, South Korea.
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Sewu DD, Boakye P, Jung H, Woo SH. Synergistic dye adsorption by biochar from co-pyrolysis of spent mushroom substrate and Saccharina japonica. Bioresour Technol 2017; 244:1142-1149. [PMID: 28869124 DOI: 10.1016/j.biortech.2017.08.103] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/13/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
The potential of activating terrestrial biomass (spent mushroom substrate, SMS) with ash-laden marine biomass [kelp seaweed, KE] via co-pyrolysis in the field of adsorption was first investigated. KE biochar (KBC), SMS biochar (SMSBC), biochar (SK10BC) from 10%-KE added SMS, and biochar (ESBC) from KE-extract added SMS were used for the adsorption of cationic dye crystal violet (CV). ESBC had highest fixed carbon content (70.60%) and biochar yield (31.6%). SK10BC exhibited high ash content, abundant functional groups, coarser surface morphology and Langmuir maximum adsorptive capacity (610.1mg/g), which is 2.2 times higher than that of SMSBC (282.9mg/g). Biochar activated by a small amount of high ash-containing biomass such as seaweed via co-pyrolysis can serve as viable alternative adsorbent for cationic dye removal.
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Affiliation(s)
- Divine Damertey Sewu
- Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon 34158, Republic of Korea
| | - Patrick Boakye
- Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon 34158, Republic of Korea
| | - Hwansoo Jung
- Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon 34158, Republic of Korea; BioGET Inc, Corporate Headquaters, Research Centre, NH05, Pai Chai University Daedeck Vally Campus, 11-3 Techno 1-ro Yuseong-gu Daejeon 34015, Republic of Korea
| | - Seung Han Woo
- Department of Chemical and Biological Engineering, Hanbat National University, 125 Dongseo-daero, Yuseong-gu, Daejeon 34158, Republic of Korea.
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Sewu DD, Boakye P, Woo SH. Highly efficient adsorption of cationic dye by biochar produced with Korean cabbage waste. Bioresour Technol 2017; 224:206-213. [PMID: 27839858 DOI: 10.1016/j.biortech.2016.11.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 11/01/2016] [Accepted: 11/02/2016] [Indexed: 05/05/2023]
Abstract
Biochar was produced from Korean cabbage (KC), rice straw (RS) and wood chip (WC) and the use as alternative adsorbents to activated carbon (AC) in wastewater treatment was investigated. Congo red (CR) and crystal violet (CV) were used as a model anionic and cationic dye, respectively. Initial solution pH had little effect on CR and CV adsorption onto all biochars except for AC on CR. The isotherm models and kinetic data showed that adsorption of CR and CV onto all biochars were dominantly by chemisorption. All biochars had lower adsorption capacity for CR than AC. KC showed higher Langmuir maximum adsorption capacity (1304mg/g) than AC (271.0mg/g), RS (620.3mg/g) and WC (195.6mg/g) for CV. KC may be a good alternative to conventional AC as cheap, superb and industrially viable adsorbent for removal of cationic dyes in wastewater.
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Affiliation(s)
- Divine D Sewu
- Department of Chemical and Biological Engineering, Hanbat National University, San 16-1, Deokmyeong-Dong, Yuseong-Gu, Daejeon 305-719, Republic of Korea
| | - Patrick Boakye
- Department of Chemical and Biological Engineering, Hanbat National University, San 16-1, Deokmyeong-Dong, Yuseong-Gu, Daejeon 305-719, Republic of Korea
| | - Seung H Woo
- Department of Chemical and Biological Engineering, Hanbat National University, San 16-1, Deokmyeong-Dong, Yuseong-Gu, Daejeon 305-719, Republic of Korea.
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Boakye P, Lee CW, Lee WM, Woo SH. The Cell Viability on Kelp and Fir Biochar and the Effect on the Field Cultivation of Corn. ACTA ACUST UNITED AC 2016. [DOI: 10.7464/ksct.2016.22.1.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Hickson F, Reid D, Weatherburn P, Stephens M, Nutland W, Boakye P. HIV, sexual risk, and ethnicity among men in England who have sex with men. Sex Transm Infect 2004; 80:443-50. [PMID: 15572611 PMCID: PMC1744930 DOI: 10.1136/sti.2004.010520] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To examine ethnic group differences in HIV testing history and sexual HIV risk behaviours that may account for such differences, among men in England who have sex with men (MSM), in order to inform HIV prevention planning priorities. METHODS A self completion survey in the summer of 2001 was carried out in collaboration with community based health promoters. Three recruitment methods were used: "gay pride" festivals, health promoter distributed leaflets, internet version advertised with gay service providers. The leaflet was produced with an alternative cover for targeted recruitment of black men. RESULTS In a sample of 13,369 MSM living in England, 17.0% were from minority ethnic groups and 5.4% had tested HIV positive. Compared to the white British majority, Asian men were 0.32 times as likely to be living with diagnosed HIV infection, while black men were 2.06 times as likely to be doing so. Among men who had not tested HIV positive, Asian men were less likely to have sex with a known HIV positive partner, while black men were more likely to have insertive unprotected anal intercourse both with a partner they knew to be HIV positive and with a partner whose HIV status they did not know. CONCLUSIONS Among MSM in England, HIV prevalence is higher among black men and lower among Asian men compared with the white British majority. Increased sexual HIV risk behaviour, especially exposure during insertive anal intercourse, accounts for some of this difference. HIV prevention programmes for MSM and African people should both prioritise black MSM.
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Affiliation(s)
- F Hickson
- Sigma Research, 64 Eurolink Centre, 49 Effra Road, London SW2 1BZ, UK.
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Bates TE, Heales SJ, Davies SE, Boakye P, Clark JB. Effects of 1-methyl-4-phenylpyridinium on isolated rat brain mitochondria: evidence for a primary involvement of energy depletion. J Neurochem 1994; 63:640-8. [PMID: 8035188 DOI: 10.1046/j.1471-4159.1994.63020640.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effects of 1-methyl-4-phenylpyridinium (MPP+) on the oxygen consumption, ATP production, H2O2 production, and mitochondrial NADH-CoQ1 reductase (complex I) activity of isolated rat brain mitochondria were investigated. Using glutamate and malate as substrates, concentrations of 10-100 microM MPP+ had no effect on state 4 (-ADP) respiration but decreased state 3 (+ADP) respiration and ATP production. Incubating mitochondria with ADP for 30 min after loading with varying concentrations of MPP+ produced a concentration-dependent decrease in H2O2 production. Incubation of mitochondria with ADP for 60 min after loading with 100 microM MPP+ caused no loss of complex I activity after washing of MPP+ from the mitochondrial membranes. These data are consistent with MPP+ initially binding specifically to complex I and inhibiting both the flow of reducing equivalents and the production of H2O2 by the mitochondrial respiratory chain, without irreversibly damaging complex I. However, mitochondria incubated with H2O2 in the presence of Cu2+ ions showed decreased complex I activity. This study provides additional evidence that cellular damage initiated by MPP+ is due primarily to energy depletion caused by specific binding to complex I, any increased damage due to free radical production by mitochondria being a secondary effect.
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Affiliation(s)
- T E Bates
- Department of Neurochemistry, Institute of Neurology, University of London, England
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Abstract
In depolarised anoxic synaptosomes, in which lactate production was significantly raised compared with normoxic conditions, calcium uptake, net acetylcholine release, and the intrasynaptosomal calcium concentration were all significantly lowered. In contrast, lactate production in synaptosomes incubated under aglycaemic- and ischaemic-type conditions was significantly lower and basal calcium uptake, acetylcholine release, and intrasynaptosomal calcium concentration were elevated compared with normoxia. In addition, the increase in intrasynaptosomal calcium concentration under the ischaemic-type condition appeared to be greater than could be accounted for by the rise in calcium uptake alone. Intrasynaptosomal pH reflected the lactate production under each condition investigated. Addition of exogenous lactate to normoxic synaptosomes mimicked the effects observed in anoxia, suggesting that lactate itself may have blocked the calcium uptake, inhibiting the rise in intrasynaptosomal calcium and acetylcholine release occurring in depolarised anoxic synaptosomes. When lactate was added to ischaemic synaptosomes, the large rise in intrasynaptosomal calcium concentration, calcium uptake, and acetylcholine release were decreased, suggesting that lactate may have a protective role in preventing cell death by calcium overload under ischaemic-type conditions. Evidence is presented to suggest that the effect of L-lactate was due to the lactate moiety itself rather than the associated acidosis.
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Affiliation(s)
- P Boakye
- Department of Biochemistry, St. Bartholomew's Hospital Medical College, University of London, England
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Affiliation(s)
- P Boakye
- Department of Biochemistry, St Bartholomew's Hospital, Medical College, University of London, U.K
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