@article { ISI:000371228200017, title = {Differentiating process performance of various coagulants in removal of congo red and orange G dyes}, journal = {International Journal of Chemical Reactor Engineering}, volume = {14}, number = {1}, year = {2016}, month = {FEB}, pages = {195-211}, publisher = {WALTER DE GRUYTER GMBH}, address = {GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY}, abstract = {

Two refractory azo dyes-Congo red and Orange G, especially at high concentrations were subjected to coagulation with different conventional coagulants and newer formulations developed from Aluminum sulfate, Iron (III) chloride, Aluminium chloride, Poly diallydimethylammonium chloride (Poly DADMAC) and Poly Aluminium Chloride (PAC). The highest COD reduction of 99 \% was obtained with PAC SAB 18 (Powder Grade PAC) for Congo red at pH 4.5 while the color removal of 99 \% was achieved with almost all the coagulants in the present study at specific pH within 3-8. The optimum dose for the iron-based coagulant is 200 mg/L while that of aluminum-based coagulants and PAC is 150-200 mg/L. Results showed that Orange G was more difficult to remove with a maximum COD removal of 65 \% and 35 \% color removal using various formulations. The combinational formulations of inorganic-inorganic and inorganic- organic produced a substantial enhancement in COD and color removal and reduced sludge. PAC-Fe30/70 produces the minimum sludge of 50 mL/g on Congo red. pH in the range 3-9 showed high reductions in COD and color (90-99 \%) for Congo red while jerky rise in COD and color reduction was observed in the case of Orange G after pH 9. An attempt to understand the dye coagulation mechanism has been made based on the specific difference in dye structure and cation speciation.

}, keywords = {coagulation, Congo red, dye removal, Orange G, Wastewater treatment}, issn = {2194-5748}, doi = {10.1515/ijcre-2015-0083}, author = {Prajapati, Kavita and Sorokhaibam, Laxmi Gayatri and Bhandari, Vinay M. and Killedar, D. J. and Ranade, Vivek V.} } @article {46060, title = {Hydrodynamic cavitation using vortex diode: an efficient approach for elimination of pathogenic bacteria from water}, journal = {Journal of Environmental Management}, volume = {242}, year = {2019}, month = {JUL }, pages = {210-219}, type = {Article}, abstract = {

The present study successfully demonstrates greener methodology of hydrodynamic cavitation using rotational flows for disinfection of water. Disinfection of two model microbial strains-gram-negative (Escherichia colt) and gram-positive (Staphylococcus aureus) using vortex diode was evaluated. The removal efficacy was quantified for two different cavitation reactors. Practically complete elimination of E. coli was achieved (99\%) after 1 h of cavitation at a pressure drop of only 0.5 bar. However, elimination of S. aureus using vortex diode was observed to be lower in comparison to the removal of E. coli and only 60\% disinfection could be achieved under similar conditions, which can be subsequently enhanced up to 98\% by increasing pressure drop. The results were compared with another cavitating device that employs linear flow for cavitation, orifice. The reactor geometry has significant impact on the disinfection process and orifice was found to require significantly higher pressure drop (10 bar) conditions for disinfection and for eliminating grain-positive bacteria with high efficiency. A plausible mechanism for disinfection was proposed to elucidate the role of cavitation in cell destruction leading to death of cells through the rupture of cell wall, oxidative damage and possible DNA denaturation. Also, a cavitation model using per pass disinfection was developed that can provide meaningful physical description of the disinfection process as against the conventional first order reaction rate model. This study would provide meaningful insight into cavitation process based on hydrodynamic cavitation for the destruction of both gram-negative and gram-positive bacteria from various water sources, including industrial wastewaters.

}, keywords = {Cavitation, Disinfection, kinetics, pollution, Wastewater treatment}, issn = {0301-4797}, doi = {10.1016/j.jenvman.2019.04.057}, author = {Jain, Pooja and Bhandari, Vinay M. and Balapure, Kshama and Jena, Jyotsnarani and Ranade, Vivek V. and Killedar, Deepak J.} } @article {46948, title = {Novel hybrid cavitation process for enhancing and altering rate of disinfection by use of natural oils derived from plants}, journal = {Ultrasonics Sonochemistry}, volume = {61}, year = {2020}, month = {MAR}, pages = {104820}, type = {Article}, abstract = {

The present study is an attempt to improvise the hydrodynamic cavitation methodology for effective disinfection of water and also to suggest prototype development for practical application. The enhancement in the disinfection efficiency was evaluated specifically for the effect of pressure, temperature, pH, microbial inoculum size and also on effect of different additives for the two model microbial strains, gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus). The efficacy of the hydrodynamic cavitation is evaluated for the two types of flows/cavitation devices - linear flow in the case of orifice and vortex flow for vortex diode. The vortex diode requires significantly lower pressures, 50\% lower as compared to orifice for the similar extent of disinfection. While the bacterial disinfection at high temperature is known, the usefulness of hydrodynamic cavitation is especially evident at ambient conditions and the process is effective even at very high concentrations of bacteria, not reported so far. The reactor geometry also has significant effect on the disinfection. The present study, for the first time, reports possible use of different natural oils such as castor oil, cinnamon oil, eucalyptus oil and clove oil in conjunction with hydrodynamic cavitation. The nature of oil modifies the cavitation behavior and an order of magnitude enhancement in the cavitation rate was observed for the two oils, eucalyptus and clove oil for a very small concentration of 0.1\%. The increased rates of disinfection, of the order of 2-4 folds, using oil can drastically reduce the time of operation and consequently reduce cost of disinfection. A possible mechanism is proposed for the effect of oil and hydrodynamic cavitation in cell destruction through the rupture of cell wall, oxidative damage and possible DNA denaturation. A cavitation model using per pass disinfection was used to correlate the data. The increased efficiency using oils and possible benefits of the developed process, where natural oils can be perceived as biocatalysts, can have significant advantages in practical applications.

}, keywords = {Antimicrobial, Cavitation, Disinfection, Oil, Wastewater treatment}, issn = {1350-4177}, doi = {10.1016/j.ultsonch.2019.104820}, author = {Mane, Maya B. and Bhandari, Vinay M. and Balapure, Kshama and Ranade, Vivek V.} } @article {47133, title = {Improving efficiency for removal of ammoniacal nitrogen from wastewaters using hydrodynamic cavitation}, journal = {Ultrasonics Sonochemistry}, volume = {70}, year = {2021}, month = {JAN}, pages = {105306}, type = {Article}, abstract = {

The present study reports significant improvements in the removal of ammoniacal nitrogen from wastewater which is an important problem for many industries such as dyes and pigment, distilleries and fisheries. Pilot plant studies (capacity, 1 m(3)/h) on synthetic wastewater using 4-amino phenol as model nitrogen containing organic compound and two real industrial effluents of high ammoniacal nitrogen content were carried out using hydrodynamic cavitation. Two reactor geometries were evaluated for increased efficiency in removal-orifice and vortex diode. Effect of initial concentration (100-500 mg/L), effect of pressure drop (0.5-5 bar) and nature of cavitating device (linear and vortex flow for cavitation) were evaluated along with effect of salt content, effect of hydrogen peroxide addition and aeration. Initial concentration was found to have significant impact on the extent of removal: similar to 5 g/m(3) removal for initial concentration of 100 mg/L and up to 12 g/m(3) removal at high concentration of 500 mg/L. Interestingly, significant improvement of the order of magnitude (up to 8 times) in removal of ammoniacal nitrogen could be obtained by sparging air or oxygen in hydrodynamic cavitation and a very high removal of above 80\% could be achieved. The removal of ammoniacal nitrogen by vortex diode was also found to be effective in the industrial wastewaters and results on two different effluent samples of distillery industry indicated up to 75\% removal, though with longer time of treatment compared to that of synthetic wastewater. The developed methodology of hydrodynamic cavitation technology with aeration and vortex diode as a cavitating device was found to be highly effective for improving the efficiency of the conventional cavitation methods and hence can be highly useful in industrial wastewater treatment, specifically for the removal of ammoniacal nitrogen.

}, keywords = {Amino phenol, Cavitation, Oxidation, pollution, Wastewater treatment}, issn = {1350-4177}, doi = {10.1016/j.ultsonch.2020.105306}, author = {Patil, Pravin B. and Bhandari, Vinay M. and Ranade, Vivek V.} } @article {48052, title = {Intensified hydrodynamic cavitation using vortex flow based cavitating device for degradation of ciprofloxacin}, journal = {Chemical Engineering Research \& Design}, volume = {187}, year = {2022}, month = {NOV}, pages = {623-632}, type = {Article}, abstract = {

The present work, for the first time, establishes degradation behavior of ciprofloxacin (CIP), a widely used fluoroquinolone group of antibiotics, using vortex flow based hydro-dynamic cavitation (HC) for low to high concentrations of CIP (10 and 100 mg/L). Effect of pressure on the degradation of CIP and TOC reduction was investigated on pilot plant scale (capacity 1 m3/h). Process intensifications using aeration as well as hydrogen per-oxide (H2O2) were also investigated. While aeration did not yield any significant en-hancement, process intensification using H2O2 resulted in similar to 200\% enhancement in the CIP degradation as compared to HC alone. Excellent degradations, to an extent of 79 \& 95\%, were achieved corresponding to high cavitational yields of 7.2 x 10-4 mg/J and 86.8 x 10-4 mg/J for CIP concentrations of 10 and 100 mg/L respectively using the process intensified approach of HC and H2O2, not reported so far for cavitating devices without moving ele-ments. The developed methodology demonstrated 4-7 times improvement in per-pass degradation and low cost with high efficiency compared to the conventional cavitation. The results clearly highlight utility of the process intensified approach using H2O2 for the degradation of CIP even at high concentrations, specifically important for pharmaceutical industries requiring zero liquid discharge norms.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Antibiotics removal, ciprofloxacin, Degradation, Oxidation, Wastewater treatment}, issn = {0263-8762}, doi = {10.1016/j.cherd.2022.09.027}, author = {Patil, Pravin B. and Thanekar, Pooja and Bhandari, Vinay M.} } @article {47996, title = {Solvent-assisted cavitation for enhanced removal of organic pollutants - degradation of 4-aminophenol}, journal = {Journal of Environmental Management}, volume = {311}, year = {2022}, month = {JUN }, pages = {114857}, type = {Article}, abstract = {

A new approach of solvent-assisted cavitation process was proposed for degradation of organic pollutants. The process envisages the use of suitable solvent as an additive, (1-5\% v/V), in the conventional cavitation process to enhance the pollutant removal efficiency. A proof of concept was provided for the removal of ammoniacal nitrogen with significantly improved efficiency using solvent-assisted hydrodynamic cavitation (HC) compared to conventional HC. The efficacy of the process was studied on a pilot plant scale (1 m(3)/h) and using vortex flow based vortex diode as a cavitating device. Degradation studies were carried out using a model pollutant, 4-amino phenol and four different solvents as additives, 1-octanol, cyclohexanol, 1-octane and toluene. Relatively polar solvents were found to increase the efficiency of the pollutant removal (\> 65\%) and also increase the rates to an extent of more than 200\%, compared to only HC. A very high removal of ammoniacal nitrogen, more than 90\%, was obtained for solvents 1-octanol and cyclohexanol, indicating the importance of the selection of solvent. Per pass degradation model showed 3 to 4 times increase in the per pass degradation for polar solvents compared to cavitation alone. The results confirm no role of conventional solvent extraction and no specific contamination of wastewater due to the use of solvent as an additive in the process. Further, the cost was 2-3 times lower as compared to the conventional HC. The interesting observations in the proposed process can fuel further research to provide possible improvements in existing methodologies of wastewater treatment, in general, and for removal of ammoniacal nitrogen, in particular.

}, keywords = {Ammoniacal nitrogen, Hydrodynamic cavitation, Oxidation, Pollution Control, Wastewater treatment}, issn = {0301-4797}, doi = {10.1016/j.jenvman.2022.114857}, author = {Patil, Pravin B. and Bhandari, Vinay M.} } @article {48267, title = {Dual activity cavitation reactors for increased efficacy in degradation of refractory pollutants-A case study on cephalexin degradation}, journal = {Chemical Engineering Research \& Design}, volume = {192}, year = {2023}, month = {APR}, pages = {310-322}, type = {Article}, abstract = {

The present work discloses a new form of cavitation processes using reactors of dual activity for increased efficiency. A proof of concept is established for the degradation of a refractory pollutant-cephalexin using both conventional and dual function cavitation reactors for the first time using acoustic and hydrodynamic cavitation (HC). A vortex diode as a cavitating device was employed for HC using aluminium as a non-catalytic and copper as dual function device for providing additional catalytic effect. The process in-tensification using hydrogen peroxide (H2O2) coupled with the dual function devices was highly effective. A negligible degradation with only HC and 81\% for HC coupled with H2O2 in 60 min for Al-vortex diode compared to 100\% degradation in only 5 min for the copper device clearly demonstrates the order of magnitude enhancements establishing dual function due to catalytic activity. Also, pH modification (pH 11) yields enhancement over 300\% for Cu-vortex diode. The use of dual function reactors drastically reduces H2O2 do-sage. The overall enhancements in the per pass degradation and cavitation yields were huge, similar to 3000\% and 1450\% respectively, highlighting the potential of the dual function ca-vitation reactors in real-life applications, not just for increased efficiencies but also for significantly reduced costs.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Advanced oxidation, Degradation, pollution, Technology, Wastewater treatment}, issn = {0263-8762}, doi = {10.1016/j.cherd.2023.02.037}, author = {Dixit, Divya and Thanekar, Pooja and Bhandari, Vinay M.} } @article {48913, title = {Enhanced degradation of metformin using surface-coated vortex diodes}, journal = {Chemical engineering and processing-process intensification }, volume = {193}, year = {2023}, month = {NOV}, type = {Article}, abstract = {

The present work successfully demonstrates, for the first time, complete degradation of metformin using newer surface-coated vortex diode (SCVD) with copper and nickel coating to provide catalytic activity in the conventional hydrodynamic cavitation (HC) for significantly enhanced degradation efficiency. The SCVDs have dual functionality and the efficacy of catalytic cavitation reactors get enhanced using process intensifications of the type H2O2 addition, pH modification, and combined approach of HC+ pH+ H2O2 apart from the advantage of low pressure drop for the vortex flow based cavitation in vortex diode (Delta P of 1 bar). Complete, 100\%, degradation of metformin (MTF) was achieved within 5 min with integration of optimized H2O2 dose and exceptionally high synergistic index value over 300, indicating extraordinary synergy for both Cu and Ni-SCVD. Acidic condition promote degradation and a complete degradation with a high 43-48\% mineralization was observed using HC+ pH 4+ (1:200) H2O2 with less intermediates formation. The SCVDs reveal remarkable enhancement of similar to 9800\% in per-pass degradation and 1400-3400\% in cavitational yield as compared to conventional cavitation process under similar conditions. The newer SCVDs with catalytic activity can provide more cost-effective solutions for industrial and real-life applications.

}, keywords = {Cavitation, Oxidation, pollution, Technology, Wastewater treatment}, issn = {0255-2701}, doi = {10.1016/j.cep.2023.109572}, author = {Dixit, Divya and Thanekar, Pooja and Bhandari, Vinay M.} } @article {48727, title = {Improving hydrodynamic cavitation using newer surface-coated cavitation reactors}, journal = {Chemical Engineering Research \& Design}, volume = {199}, year = {2023}, month = {NOV}, pages = {238-251}, type = {Article}, abstract = {

Surface-coated cavitation devices, vortex diode (SCVD) have been reported for the first time for enhancing efficiency of hydrodynamic cavitation (HC). Two surface-coated cavitation reactors using coating of copper and nickel (-50 mu m) were evaluated, also comparing results with conventional reactor vortex diode. The proof of concept is successfully demonstrated for complete degradation of two model organic pollutants, antibioticscephalexin (CFX) and ciprofloxacin (CIP). The surface-coated reactors provide dual activity, and the catalytic effect is highly pronounced with process intensification using H2O2 and/ or pH alternations. Integration of SCVD, pH and H2O2 was the most effective strategy. Complete degradation of the antibiotics was achieved within minutes with H2O2 (-1000 molar ratio) for both Cu and Ni-surface-coated cavitation reactors compared to lower degradation of-19\% for CFX and-37\% for CIP using only HC. An excellent enhancement of over 300\% for CFX degradation at pH 11 and-170\% for CIP degradation at pH 4 was obtained. Huge enhancements in per-pass degradation and cavitational yields (up to 400 times) clearly highlight the utility of the surface-coated cavitation reactors in various applications and for cost-effectiveness.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Hydrodynamic cavitation, Oxidation, pollution, Reactor, Technology, Wastewater treatment}, issn = {0263-8762}, doi = {10.1016/j.cherd.2023.10.002}, author = {Dixit, Divya and Thanekar, Pooja and Bhandari, Vinay M.} }