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Sahu JN, Acharya J, Meikap BC. Response surface modeling and optimization of chromium(VI) removal from aqueous solution using Tamarind wood activated carbon in batch process. JOURNAL OF HAZARDOUS MATERIALS 2009; 172:818-825. [PMID: 19748729 DOI: 10.1016/j.jhazmat.2009.07.075] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 03/26/2009] [Accepted: 07/18/2009] [Indexed: 05/28/2023]
Abstract
The present paper discusses response surface methodology (RSM) as an efficient approach for predictive model building and optimization of chromium adsorption on developed activated carbon. In this work the application of RSM is presented for optimizing the removal of Cr(VI) ions from aqua solutions using activated carbon as adsorbent. All experiments were performed according to statistical designs in order to develop the predictive regression models used for optimization. The optimization of adsorption of chromium on activated carbon was carried out to ensure a high adsorption efficiency at low adsorbent dose and high initial concentration of Cr(VI). While the goal of adsorption of chromium optimization was to improve adsorption conditions in batch process, i.e., to minimize the adsorbent dose and to increase the initial concentration of Cr(VI). In the adsorption experiments a laboratory developed Tamarind wood activated carbon made of chemical activation (zinc chloride) was used. A 2(4) full factorial central composite design experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value (R(2)=0.928) and satisfactory prediction second-order regression model was derived. Maximum chromium removal efficiency was predicted and experimentally validated. The optimum adsorbent dose, temperature, initial concentration of Cr(VI) and initial pH of the Cr(VI) solution were found to be 4.3g/l, 32 degrees C, 20.15 mg/l and 5.41 respectively. Under optimal value of process parameters, high removal (>89%) was obtained for Cr(VI).
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Singh CK, Sahu JN, Mahalik KK, Mohanty CR, Mohan BR, Meikap BC. Studies on the removal of Pb(II) from wastewater by activated carbon developed from Tamarind wood activated with sulphuric acid. JOURNAL OF HAZARDOUS MATERIALS 2008; 153:221-8. [PMID: 17889434 DOI: 10.1016/j.jhazmat.2007.08.043] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Revised: 08/04/2007] [Accepted: 08/16/2007] [Indexed: 05/11/2023]
Abstract
The low-cost activated carbon were prepared from Tamarind wood material by chemical activation with sulphuric acid for the adsorption of Pb(II) from dilute aqueous solution. The activated carbon developed shows substantial capacity to adsorb Pb(II) from dilute aqueous solutions. The parameters studied include physical and chemical properties of adsorbent, pH, adsorbent dose, contact time and initial concentrations. The kinetic data were best fitted to the Lagergren pseudo-first-order and pseudo-second order models. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The maximum removal of lead(II) was obtained 97.95% (experimental) and 134.22 mg/g (from Langmuir isotherm model) at initial concentration 40 mg/l, adsorbent dose 3g/l and pH 6.5. This high uptake showed Tamarind wood activated carbon as among the best adsorbents for Pb(II).
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Sahu JN, Acharya J, Meikap BC. Optimization of production conditions for activated carbons from Tamarind wood by zinc chloride using response surface methodology. BIORESOURCE TECHNOLOGY 2010; 101:1974-1982. [PMID: 19913410 DOI: 10.1016/j.biortech.2009.10.031] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Revised: 10/12/2009] [Accepted: 10/14/2009] [Indexed: 05/28/2023]
Abstract
The low-cost activated carbon was prepared from Tamarind wood an agricultural waste material, by chemical activation with zinc chloride. Activated carbon adsorption is an effective means for reducing organic chemicals, chlorine, heavy metals and unpleasant tastes and odours in effluent or colored substances from gas or liquid streams. Central composite design (CCD) was applied to study the influence of activation temperature, chemical ratio of zinc chloride to Tamarind wood and activation time on the chemical activation process of Tamarind wood. Two quadratic models were developed for yield of activated carbon and adsorption of malachite green oxalate using Design-Expert software. The models were used to calculate the optimum operating conditions for production of activated carbon providing a compromise between yield and adsorption of the process. The yield (45.26 wt.%) and adsorption (99.9%) of the activated carbon produced at these operating conditions showed an excellent agreement with the amounts predicted by the models.
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Meikap BC, Purohit NK, Mahadevan V. Effect of microwave pretreatment of coal for improvement of rheological characteristics of coal–water slurries. J Colloid Interface Sci 2005; 281:225-35. [PMID: 15567400 DOI: 10.1016/j.jcis.2004.08.084] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2004] [Accepted: 08/10/2004] [Indexed: 11/30/2022]
Abstract
Indian high-ash coal contains alpha-silica components of the mineral matter. When coal is transported in the form of a slurry, alpha-silica adds to the settling properties of coal and enhances erosion of pipelines. As such any technique that will contribute to changing the characteristics of mineral matter by selective demineralization is bound to supplement the knowledge of coal slurries in the science of rheology. One such method is the use of a novel microwave technology, which changes the alpha-silica to less harmful beta-silica. Thus microwave-treated coal slurry facilitates enhanced flow characteristics and abates the erosion problem in pipeline transport as well as in coal-slurry injection furnaces. This paper reports on the rheological study of closely sized coal particles of medium-volatile, low-ash, low-moisture cleans and high-ash rejects with and without microwave treatment. Viscosity of suspensions of microwave-treated coal was found to be less than that of untreated coal, in the case of both cleans and rejects. Microwave pretreatment thus reduces the viscosity and the pumping cost and opens a new outlook for pipeline transport. An attempt has been made to quantify the improvement of rheological characteristics due to microwave pretreatment.
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Dwivedi CP, Sahu JN, Mohanty CR, Mohan BR, Meikap BC. Column performance of granular activated carbon packed bed for Pb(II) removal. JOURNAL OF HAZARDOUS MATERIALS 2008; 156:596-603. [PMID: 18249492 DOI: 10.1016/j.jhazmat.2007.12.097] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2007] [Revised: 12/16/2007] [Accepted: 12/17/2007] [Indexed: 05/25/2023]
Abstract
The excessive release of lead from lead acid batteries, smelting plant into the environment is a major concern worldwide. Adsorption process is among the most effective techniques for lead removal from wastewater and activated carbon has been widely used as an adsorbent. In this paper an attempt has been made to investigate the adsorption behaviour of Pb(II) from aqueous systems onto granular activated carbon using the batch mode and continuous mode in a packed bed column with more successive service and regeneration. The experiments were performed at constant temperature and dimensions of column and packed bed of granular activated carbon with variation of flows through the bed and concentrations of lead solutions. Breakthrough points were found out for the adsorption of lead on the adsorbent using continuous-flow column operation by varying different operating parameters like hydraulic loading rate from 4 to 16 m(3)/h m(2) and feed concentrates from 20 to 60 mg/l. Granular activated carbon column regeneration using 0.5 M concentration of HNO(3) has been investigated. Results indicate encouraging performance towards removal of Pb(II).
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Rastogi K, Sahu JN, Meikap BC, Biswas MN. Removal of methylene blue from wastewater using fly ash as an adsorbent by hydrocyclone. JOURNAL OF HAZARDOUS MATERIALS 2008; 158:531-540. [PMID: 18339480 DOI: 10.1016/j.jhazmat.2008.01.105] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/28/2008] [Accepted: 01/30/2008] [Indexed: 05/26/2023]
Abstract
The excessive release of color into the environment is a major concern worldwide. Adsorption process is among the most effective techniques for color removal from wastewater and fly ash has been widely used as an adsorbent. Therefore, this study was carried out to understand the adsorption behavior of methylene blue from aqueous systems onto fly ash using the continuous mode. Continuous mode sorption experiments were carried out to remove methylene blue from its aqueous solutions in hydrocyclone equipment. The experiments were performed at constant temperature and dimensions of hydrocyclone with variation of flows through the equipment, concentrations of methylene blue solutions and fly ash concentration, respectively. A maximum removal of 58.24% was observed at adsorbent dosage of 900 mg/l at pH 6.75 for an initial methylene blue concentration of 65 mg/l.
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Kumari U, Behera SK, Meikap BC. A novel acid modified alumina adsorbent with enhanced defluoridation property: Kinetics, isotherm study and applicability on industrial wastewater. JOURNAL OF HAZARDOUS MATERIALS 2019; 365:868-882. [PMID: 30497041 DOI: 10.1016/j.jhazmat.2018.11.064] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/15/2018] [Accepted: 11/15/2018] [Indexed: 06/09/2023]
Abstract
Excessive fluoride contamination in ground and surface water is hazardous to human health. Adsorptive removal is a better option for defluoridation due to its simplicity and efficient working property. In the current research, an attempt was made for the removal of fluoride ions from wastewater by a novel adsorbent synthesized with alumina and H2SO4 acid by acidic activation. The adsorbent was characterized for physio-chemical properties by several analytical methods (SEM, EDX, FTIR, XRF, TGA, XRD, HI and pHZPC). The specific surface area of acid activated alumina (AAA) adsorbent was found to be 87.44 m2/g. The batch scale experiments were conducted to study the effect of initial pH, adsorbent dose, stirring rate, and contact time on the defluoridation efficiency of AAA adsorbent. The experimental data of isotherm study was found to follow the Freundlich isotherm model. The maximum adsorption capacity of fluoride on AAA was 69.52 mg/g at 318 K. The nature of adsorption was found to be endothermic and spontaneous. The adsorption kinetic data followed the pseudo-second-order model. The fluoride removal efficiency of alumina with and without acid activation resulted in 96.72% and 63.58%, respectively. The regeneration capability, reusability, applicability on industrial effluent and economic value were investigated.
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Kumari U, Behera SK, Siddiqi H, Meikap BC. Facile method to synthesize efficient adsorbent from alumina by nitric acid activation: Batch scale defluoridation, kinetics, isotherm studies and implementation on industrial wastewater treatment. JOURNAL OF HAZARDOUS MATERIALS 2020; 381:120917. [PMID: 31376661 DOI: 10.1016/j.jhazmat.2019.120917] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
The excess amount of fluoride contamination in the groundwater or industrial effluents fosters various health problems. Considering the advantages of adsorption, the current research reports the synthesis of a novel adsorbent (HNAA) by simple and convenient process of nitric acid activation of alumina. The physiochemical characterization (SEM, EDX, XRF, FTIR, BET, and pHZPC) results exhibited successful activation of alumina and adsorption of fluoride ions. The effect of process parameters (contact time, initial pH, adsorbent dose, initial fluoride concentration and presence of coexisting ions) on adsorption of fluoride ions on HNAA were investigated in batch scale. The adsorption of fluoride ion on HNAA followed the Freundlich isotherm and pseudo second order kinetic model. The Qmax of HNAA adsorbent was 45.75 mg/g at 45 °C. The fluoride ion adsorption was revealed to be endothermic and spontaneous. The experimentation of the HNAA adsorbent on industrial wastewater, with fluoride concentration of 17.5 mg/L, inferred the significant defluoridation potential at the optimized adsorbent dose and pH. The nitric acid activation of alumina resulted in improvement of defluoridation efficiency from 74.18% to 97.43%. The HNAA also exhibited the better regeneration and reusability features which distinguish it as a promising adsorbent to be applied for real field wastewater.
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Biswas S, Sen TK, Yeneneh AM, Meikap BC. Synthesis and characterization of a novel Ca-alginate-biochar composite as efficient zinc (Zn2+) adsorbent: Thermodynamics, process design, mass transfer and isotherm modeling. SEP SCI TECHNOL 2018. [DOI: 10.1080/01496395.2018.1527353] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Sahu JN, Agarwal S, Meikap BC, Biswas MN. Performance of a modified multi-stage bubble column reactor for lead(II) and biological oxygen demand removal from wastewater using activated rice husk. JOURNAL OF HAZARDOUS MATERIALS 2009; 161:317-324. [PMID: 18462879 DOI: 10.1016/j.jhazmat.2008.03.094] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 03/20/2008] [Accepted: 03/20/2008] [Indexed: 05/26/2023]
Abstract
The excessive release of wastewater into the environment is a major concern worldwide. Adsorption is the one of the most effective technique for treatment of wastewater. In this work activated carbon prepared from rice husk has been used as an adsorbent. In the present investigation a three phase modified multi-stage bubble column reactor (MMBCR) has been designed to remove lead and biochemical oxygen demand (BOD) from wastewater by means of its adsorption onto the surface of activated rice husk. The multi-staging has been achieved by hydrodynamically induced continuous bubble generation, breakup and regeneration. Under optimum conditions, maximum lead and BOD reduction achieved using activated rice husk was 77.15% and 19.05%, respectively. Results showed MMBCR offered appreciated potential benefits for lead removal from wastewater and BOD removal, even this extent of removal is encouraging and the MMBCR can be used a pretreatment unit before subjecting the wastewater to biological treatment.
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Mahalik K, Sahu JN, Patwardhan AV, Meikap BC. Statistical modelling and optimization of hydrolysis of urea to generate ammonia for flue gas conditioning. JOURNAL OF HAZARDOUS MATERIALS 2010; 182:603-10. [PMID: 20643504 DOI: 10.1016/j.jhazmat.2010.06.075] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 06/18/2010] [Accepted: 06/18/2010] [Indexed: 05/14/2023]
Abstract
The present study is concerned with the technique of producing a relatively small quantity of ammonia which can be used safely in a coal-fired thermal power plant to improve the efficiency of electrostatic precipitator by removing the suspended particulate material mostly fly ash, from the flue gas. In this work hydrolysis of urea has been conducted in a batch reactor at atmospheric pressure to study the different reaction variables such as reaction temperature, initial concentration and stirring speed on the conversion by using design expert software. A 2(3) full factorial central composite design (CCD) has been employed and a quadratic model equation has been developed. The study reveals that conversion increases exponentially with an increase in temperature, stirring speed and feed concentration. However the stirring speed has the greatest effect on the conversion with concentration and temperature exerting least and moderate effect respectively. The values of equilibrium conversion obtained through the developed models are found to agree well with their corresponding experimental counterparts with a satisfactory correlation coefficient of 93%. The developed quadratic model was optimized using quadratic programming to maximize conversion of urea within experimental range studied. The optimum production condition has been found to be at the temperature of 130 degrees C, feed concentration of 4.16 mol/l and stirring speed of 400 rpm and the corresponding conversion, 63.242%.
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Behera ID, Nayak M, Biswas S, Meikap BC, Sen R. Enhanced biodegradation of total petroleum hydrocarbons by implementing a novel two-step bioaugmentation strategy using indigenous bacterial consortium. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 292:112746. [PMID: 34022651 DOI: 10.1016/j.jenvman.2021.112746] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/12/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
In the present study, a two-step bioaugmentation strategy (TSBS) was implemented by using indigenous bacterial consortium to enhance the degradation of total petroleum hydrocarbons (TPH) from petroleum refinery sludge (PRS). A bacterial consortium was developed using four indigenous isolated strains, Dietzia sp. IRB191, Dietzia sp. IRB192, Staphylococcus sp. BSM19 and Stenotrophomonas sp. IRB19 from PRS. The optimum conditions of pH, temperature, and sludge concentration were 7, 34 °C, and 2% (w/v), respectively, for maximum TPH degradation, obtained using one variable at a time approach. Under the optimal culture conditions, the developed consortium was inoculated twice to the culturing medium, at the beginning (0th day) and again on the 10th day for implementing a novel TSBS. The maximum TPH degradation of 91.5 ± 2.28% was found with TSBS, which was 1.18 times higher than that of SSBS (77.3 ± 2.6%) in 15 days of incubation. GC-FID study also confirmed that the TPH present in the PRS was effectively degraded by the bacterial consortium with TSBS. The TPH degradation by using TSBS proceeded according to the first-order kinetics with a rate constant of 0.155 d-1. Hence, biodegradation using a TSBS can be considered an effective and eco-friendly process for safe disposal of petroleum refinery sludge.
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Mahalik K, Sahu JN, Patwardhan AV, Meikap BC. Kinetic studies on hydrolysis of urea in a semi-batch reactor at atmospheric pressure for safe use of ammonia in a power plant for flue gas conditioning. JOURNAL OF HAZARDOUS MATERIALS 2010; 175:629-637. [PMID: 19914776 DOI: 10.1016/j.jhazmat.2009.10.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2009] [Revised: 10/14/2009] [Accepted: 10/14/2009] [Indexed: 05/28/2023]
Abstract
With growing industrialization in power sector, air is being polluted with a host of substances-most conspicuously with suspended particulate matter emanating from coal-fired thermal power plants. Flue gas conditioning, especially in such power plants, requires in situ generation of ammonia. In the present paper, experiments for kinetic study of hydrolysis of urea have been conducted using a borosil glass reactor, first without stirring followed by with stirring. The study reveals that conversion increases exponentially with an increase in temperature and feed concentration. Furthermore, the effect of stirring speed, temperature and concentration on conversion has been studied. Using collision theory, temperature dependency of forward rate constant has been developed from which activation energy of the reaction and the frequency factors have been calculated. It has been observed that the forward rate constant increases with an increase in temperature. The activation energy and frequency factor with stirring has been found to be 59.85 kJ/mol and 3.9 x 10(6)min(-1) respectively with correlation co-efficient and standard deviation being 0.98% and +/-0.1% in that order.
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Mukherjee S, Boral S, Siddiqi H, Mishra A, Meikap BC. Present cum future of SARS-CoV-2 virus and its associated control of virus-laden air pollutants leading to potential environmental threat - A global review. JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 2021; 9:104973. [PMID: 33462561 PMCID: PMC7805399 DOI: 10.1016/j.jece.2020.104973] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/06/2020] [Accepted: 12/20/2020] [Indexed: 05/05/2023]
Abstract
The world is presently infected by the biological fever of COVID-19 caused by SARS-CoV-2 virus. The present study is mainly related to the airborne transmission of novel coronavirus through airway. Similarly, our mother planet is suffering from drastic effects of air pollution. There are sufficient probabilities or evidences proven for contagious virus transmission through polluted airborne-pathway in formed aerosol molecules. The pathways and sources of spread are detailed along with the best possible green control technologies or ideas to hinder further transmission. The combined effects of such root causes and unwanted outcomes are similar in nature leading to acute cardiac arrest of our planet. To maintain environmental sustainability, the prior future of such emerging unknown biological hazardous air emissions is to be thoroughly researched. So it is high time to deal with the future of hazardous air pollution and work on its preventive measures. The lifetime of such an airborne virus continues for several hours, thus imposing severe threat even during post-lockdown phase. The world waits eagerly for the development of successful vaccination or medication but the possible outcome is quite uncertain in terms of equivalent economy distribution and biomedical availability. Thus, risk assessments are to be carried out even during the post-vaccination period with proper environmental surveillance and monitoring. The skilled techniques of disinfection, sanitization, and other viable wayouts are to be modified with time, place, and prevailing climatic conditions, handling the pandemic efficiently. A healthy atmosphere makes the earth a better place to dwell, ensuring its future lifecycle.
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Key Words
- 2019-nCoV, 2019 novel coronavirus
- ACE2, angiotensin-converting enzyme 2
- ALRI, Acute Lower Respiratory Infections
- ANN, artificial neural network
- API, air pollution index
- ASTM, American Society for Testing and Materials
- Aerosol or particulate matter
- Airborne virus
- BCG, Bacillus Calmette Guérin
- COCOREC, Collaborative Study COVID Recurrence
- COPD, Chronic Obstructive Pulmonary Disorder
- COVID-19, coronavirus disease, 2019
- CSG, Coronavirus Study Group
- CoV, Coronavirus
- Dispersion
- EPA, Environmental Protection Agency
- FCVS, filtered containment venting systems
- HEME, High-Efficiency Mist Eliminator
- ICTV, International Committee on Taxonomy of Viruses
- IHD, Ischemic Heart Disease
- ISO, International organization of Standardization
- IoT, Internet of Things
- MERS-CoV, Middle-East Respiratory Syndrome coronavirus
- NAAQS, National Ambient Air Quality Standard
- NFKB, nuclear factor kappa-light-chain-enhancer of activated B cells
- NRF2, nuclear factor erythroid 2-related factor 2
- Novel coronavirus
- PM, particulate matter
- Pathways of transmission
- Prevention and control measures
- ROS, reactive oxygen species
- SARS-CoV-2
- SARS-CoV-2, severe acute respiratory syndrome coronavirus 2
- USEPA, United States Environmental Protection Agency
- UVGI, Ultraviolet Germicidal Irradiation
- VOC, volatile organic compound
- WHO, World Health Organization
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Kurella S, Bhukya PK, Meikap BC. Removal of H 2S pollutant from gasifier syngas by a multistage dual-flow sieve plate column wet scrubber. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2017; 52:515-523. [PMID: 28276891 DOI: 10.1080/10934529.2017.1281690] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The objective of this study was to observe the performance of a lab-scale three-stage dual-flow sieve plate column scrubber for hydrogen sulfide (H2S) gas removal from a gas stream, in which the H2S concentration was similar to that of gasifier syngas. The tap water was used as scrubbing liquid. The gas and liquid were operated at flow rates in the range of 16.59 × 10-4-27.65 × 10-4 Nm3/s and 20.649 × 10-6-48.183 × 10-6 m3/s, respectively. The effects of gas and liquid flow rates on the percentage removal of H2S were studied at 50-300 ppm inlet concentrations of H2S. The increase in liquid flow rate, gas flow rate and inlet H2S concentration increased the percentage removal of H2S. The maximum of 78.88% removal of H2S was observed at 27.65 × 10-4 Nm3/s gas flow rate and 48.183 × 10-6 m3/s liquid flow rate for 300 ppm inlet concentration of H2S. A model has also been developed to predict the H2S gas removal by using the results from the experiments and adding the parameters that affect the scrubber's performance. The deviations between experimental and predicted H2S percentage removal values were observed as less than 16%.
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Bal M, Reddy TT, Meikap BC. Removal of HCl gas from off gases using self-priming venturi scrubber. JOURNAL OF HAZARDOUS MATERIALS 2019; 364:406-418. [PMID: 30384251 DOI: 10.1016/j.jhazmat.2018.10.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 06/08/2023]
Abstract
Growing concern about the effect of hydrochloric acid gas (HCl) on environment and abatement of it is now a very serious issue. This present paper is focused on developing a realistic model in order to remove the HCl from the off gases using self-priming venturi scrubber. A detailed parametric study of throat gas velocity (36-72 m/s), liquid level in outer cylinder (0.40-0.77 m) and inlet concentration of HCl (100-500 ppm) on HCl removal efficiency have been done with normal water as a scrubbing liquid. Also the removal efficiency was enhanced by using NaOH solution as a scrubbing liquid in submerged and non-submerged conditions. Therefore, the maximum removal efficiency of HCl was obtained as 87.83% with normal water and 92.54% with 0.005N NaOH solution as the scrubbing liquid at inlet HCl concentration of 500 ppm, throat gas velocity of 60 m/s and liquid level of 0.77 m in submerged condition. Experimental results were validated with the developed empirical model and showed excellent agreement with less deviation.
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Meikap BC, Kundu G, Biswas MN. Mass Transfer Characteristics of a Counter Current Multi-Stage Bubble Column Scrubber. JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 2004. [DOI: 10.1252/jcej.37.1185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sahu JN, Kapelyushin Y, Mishra DP, Ghosh P, Sahoo BK, Trofimov E, Meikap BC. Utilization of ferrous slags as coagulants, filters, adsorbents, neutralizers/stabilizers, catalysts, additives, and bed materials for water and wastewater treatment: A review. CHEMOSPHERE 2023; 325:138201. [PMID: 36863629 DOI: 10.1016/j.chemosphere.2023.138201] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/05/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Solid waste is currently produced in substantial amounts by industrial activities. While some are recycled, the majority of them are dumped in landfills. Iron and steel production leaves behind ferrous slag, which must be created organically, managed wisely and scientifically if the sector is to remain more sustainably maintained. Ferrous slag is the term for the solid waste that is produced when raw iron is smelted in ironworks and during the production of steel. Both its specific surface area and porosity are relatively high. Since these industrial waste materials are so easily accessible and offer such serious disposal challenges, the idea of their reuse in water and wastewater treatment systems is an appealing alternative. There are many components such as Fe, Na, Ca, Mg, and silicon found in ferrous slags, which make it an ideal substance for wastewater treatment. This research investigates the potential of ferrous slag as coagulants, filters, adsorbents, neutralizers/stabilizers, supplementary filler material in soil aquifers, and engineered wetland bed media to remove contaminants from water and wastewater. Ferrous slag may provide a substantial environmental risk before or after reuse, so leaching and eco-toxicological investigations are necessary. Some study revealed that the amount of heavy metal ions leached from ferrous slag conforms to industrial norms and is exceedingly safe, hence it may be employed as a new type of inexpensive material to remove contaminants from wastewater. The practical relevance and significance of these aspects are attempted to be analyzed, taking into account all recent advancements in the fields, in order to help in the development of informed decisions about future directions for research and development related to the utilization of ferrous slags for wastewater treatment.
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Sahu JN, Mahalik KK, Patwardhan AV, Meikap BC. Equilibrium studies on hydrolysis of urea in a semi-batch reactor for production of ammonia to reduce hazardous pollutants from flue gases. JOURNAL OF HAZARDOUS MATERIALS 2009; 164:659-664. [PMID: 18823705 DOI: 10.1016/j.jhazmat.2008.08.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Revised: 06/24/2008] [Accepted: 08/15/2008] [Indexed: 05/26/2023]
Abstract
The increasing environmental awareness and the mandate of the pollution control agencies in various part of country for lowering emission of air pollutants such as CO(2), NO(x), SO(2) and fly ash emissions, has increased the urgency for reviewing options and alternatives to accomplish the above objective. The addition of ammonia into the flue gas stream as a conditioning agent is found to be used in recent years for the reduction of air pollutants. Flue gas conditioning requires in situ generation of ammonia as the transportation and storage of anhydrous ammonia is hazardous in nature. The equilibrium study on hydrolysis of urea was done in a semi-batch glass reactor to investigate the effect of reaction temperature, initial feed concentration and stirring speed on ammonia production. Few experiments were carried out in a semi-batch reactor at atmospheric pressure by using different concentration of urea solution from 10 to 40 wt% of urea to water and equilibrium study has been done. The study reveals that conversion increases exponentially with an increase in temperature but the conversion decreases with increase in the inlet feed concentration of urea solution. Furthermore, the effect of stirring speed on conversion has also been studied and it found that conversion increases with increase in stirring speed.
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Patra G, Das P, Chakraborty S, Meikap BC. Removal of fluoride from wastewater using HCl-treated activated alumina in a ribbed hydrocyclone separator. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2018; 53:601-608. [PMID: 29381416 DOI: 10.1080/10934529.2018.1429728] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Excessive fluoride concentration in wastewater is a major health concern worldwide. The main objective of wastewater treatment is to allow industrial effluents to be disposed of without danger to the human health and the natural environment. In this current study, experiments have been conducted to remove fluoride from aqueous solution using alumina and HCl (Hydrochloric acid) treated activated alumina in a continuous mode. A spiral rib was introduced in the cylindrical part of the conventional hydrocyclone to increase the performance, and the new hydrocyclone is dubbed as ribbed hydrocyclone. Experiments were carried out to analyze the performance of the ribbed hydrocyclone and compared the results with the conventional hydrocyclone of the same dimension. The efficiency of conventional and ribbed hydrocyclone at a slurry flow rate of 50 LPM (liter per minute) for the solid concentration of 1.4 wt% were 80% and 93.5% respectively. The cut size d50 of the conventional and ribbed hydrocyclone was 18 µm and 13 µm respectively at a slurry velocity of 50 LPM. Fluoride removal efficiency using alumina and HCl-treated alumina was also investigated in a continuous mode by the ribbed hydrocyclone. Maximum fluoride removal efficiency was 49.5%, and 80% for alumina and HCl-treated alumina for the initial concentration of 10 mg/L at a slurry flow rate of 50 LPM.
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Kurella S, Meikap BC. Removal of fly-ash and dust particulate matters from syngas produced by gasification of coal by using a multi-stage dual-flow sieve plate wet scrubber. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2016; 51:870-876. [PMID: 27230635 DOI: 10.1080/10934529.2016.1181465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, fly-ash water scrubbing experiments were conducted in a three-stage lab-scale dual-flow sieve plate scrubber to observe the performance of scrubber in fly-ash removal at different operating conditions by varying the liquid rate, gas rate and inlet fly-ash loading. The percentage of fly-ash removal efficiency increases with increase in inlet fly-ash loading, gas flow rate and liquid flow rate, and height of the scrubber; 98.55% maximum percentage of fly-ash removal efficiency (ηFA) is achieved at 19.36 × 10(-4) Nm(3)/s gas flow rate (QG) and 48.183 × 10(-6) m(3)/s liquid flow rate (QL) at 25 × 10(-3) kg/Nm(3) inlet fly-ash loading (CFA,i). A model has also been developed for the prediction of fly-ash removal efficiency of the column using the experimental results. The predicted values calculated using the correlation matched well with the experimental results. Deviations observed between the experimental and the predicted values were less than 20%.
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Sahu JN, Gangadharan P, Meikap BC. Optimization process parameters for in-situ synthesis of ammonia by catalytic hydrolysis of urea with fly ash in a batch reactor for safe feedstock in power plants. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2011; 46:874-886. [PMID: 21714628 DOI: 10.1080/10934529.2011.580200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this study, catalytic urea hydrolysis for production of ammonia in presence of fly ash, at optimum condition, was investigated in a batch reactor. The single and combined effects of operating parameters such as initial feed concentrations, temperature, fly ash doses, times and stirring speed on the production of ammonia from urea were analyzed using response surface methodology. A 2(5) full factorial central composite experimental design was employed. Analysis of variance (ANOVA) showed a high coefficient of determination value (R(2)= 0.963) and satisfactory prediction second order regression model was derived. The optimum production conditions were determined as initial feed concentration 19.9 wt. % of urea, temperature 175°C, fly ash dose 7.5 g/L, reaction time 25 min and stirring speed 769 rpm. At optimum conversion conditions, the conversion of urea for production of ammonia was found to be 99.8 %.
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Kumari U, Behera SK, Meikap BC. Defluoridation of synthetic and industrial wastewater by using acidic activated alumina adsorbent: characterization and optimization by response surface methodology. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2018; 54:79-88. [PMID: 30406701 DOI: 10.1080/10934529.2018.1521674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/29/2018] [Accepted: 09/06/2018] [Indexed: 06/08/2023]
Abstract
Excessive contamination of fluoride in wastewater is the cause of several chronic health problems. For this purpose, an adsorbent was prepared from alumina by acidic activation using sulfuric acid. The current research aims to find the maximum fluoride adsorption (%) from synthetic and industrial wastewater at optimum process parameters by using response surface methodology (RSM). All batch scale experiments were carried out according to the statistical-design order. Central composite design (CCD) was applied to ascertain the effect of adsorbent dose, pH, initial fluoride concentration and temperature on fluoride adsorption (%). Maximum fluoride removal was predicted based on the quadratic model developed. Validation of the model was done with negligible error. The regression coefficient of the model was found to be 0.96. From the analysis of variance (ANOVA), the factors with the greatest effect on the adsorption of fluoride were identified. Under optimized condition, the adsorbent dose 13.89 g L-1, pH 5.52, temperature 25 °C and initial fluoride concentration 18.67 mg L-1 resulted in 96% of maximum fluoride adsorption. Under the same optimized parameters, the fluoride adsorption from industrial wastewater found to be 92.10%.
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Bal M, Biswas S, Behera SK, Meikap BC. Modeling and optimization of process variables for HCl gas removal by response surface methodology. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2019; 54:359-366. [PMID: 30628528 DOI: 10.1080/10934529.2018.1551650] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 11/15/2018] [Accepted: 11/18/2018] [Indexed: 06/09/2023]
Abstract
In the present article, optimization of process variables has been done to maximize the removal efficiency of toxic HCl gas in a submerged self-priming venturi scrubber. Response surface methodology with central composite design has been chosen to predict the effect of process variables on the removal efficiency. A quadratic equation was found from this study to predict the removal efficiency and from the ANOVA test, the significance of process variables was evaluated. Regression analysis confirmed the suitability of the developed model by the higher R2 square value (0.9717). Optimum conditions were obtained as 55.18 m s-1 of throat gas velocity, 405.10 ppm of inlet HCl concentration and 0.0038 N of NaOH concentration in scrubbing liquid to achieve 90.80% of the HCl removal efficiency.
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Richhariya G, Meikap BC, Kumar A. Review on fabrication methodologies and its impacts on performance of dye-sensitized solar cells. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:15233-15251. [PMID: 34978676 DOI: 10.1007/s11356-021-18049-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
This review highlights and summarizes the impact of different fabrication processes on the efficiency of dye-sensitized solar cells (DSSCs). Energy conversion efficiency of cell depends upon semiconductor, sensitizer, electrolyte, and counter electrode. Efficiency of DSSCs can be enhanced by properly selecting the optimum significance of various parameters of fabrications process. Major challenges of these solar cells are non-vegetal, noxious, extreme sensitizers. Application of natural dyes in this field plays a significant role. An optimized CdSe-TiO2 photoanode showed a power conversion efficiency (PCE) of 13.29% and short circuit current density of 15.30 mA cm-2 for the DSSC. Power conversion efficiency of 3.26% was achieved by using TTO electrode for DSSC device that is ascribed to the improved electrical and optical properties due to doping with Ta element. Absorbance of betalain was shown in the visible range of 530-535 nm for betanin while 450-559 nm for anthocyanin pigment. The natural dyes are economical, readily available, and environmentally friendly. This compilation would be beneficial for researchers working on dye solar cell.
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