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Journal ArticleDOI: 10.1080/00986445.2020.1715955

Promotion of clinoptilolite adsorption for azithromycin antibiotic by Tween 80 and Triton X-100 surface modifiers under batch and fixed-bed processes

04 Mar 2021-Chemical Engineering Communications (Taylor & Francis)-Vol. 208, Iss: 3, pp 328-348
Abstract: In this study, azithromycin (AZT) adsorbed on natural clinoptilolite (NC) modified by Triton X-100 (NC-Triton) and Tween 80 (NC-Tween) surfactants. The effect of pH, contact time, adsorbent dose, a...

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Topics: Clinoptilolite (53%), Adsorption (52%), Triton X-100 (51%)
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5 results found


Journal ArticleDOI: 10.1016/J.MSEC.2020.111401
Abstract: The precise and rapid detection of hazardous molecules, microorganisms, pollutants, and toxins currently remains a global challenge. Aflatoxin B1 (AFB1) is a toxic and dangerous product of fungi that considered as cancerogenic, mutagenic, and immunosuppressive for humans and animals. Therefore, the screening of AFB1 in food and beverages plays an important role in preventing foodborne illnesses. In this study, AFB1 molecules were detected in a microfluidic device with integrated polyacrylonitrile/zinc oxide (PAN/ZnO) nanofibers fabricated via a combination of the electrospinning, and atomic layer deposition (ALD) techniques. The structural and optical analyses of PAN/ZnO nanofibers were performed and samples with the most suitable properties were utilized for AFB1 detection. In order to obtain the biorecognition layer towards AFB1, PAN/ZnO samples were modified by (3-Aminopropyl) triethoxysilane (APTES), and glutaraldehyde (GA), bovine serum albumin (BSA) and monoclonal antibodies (Anti-AFB1). Subsequently, photoluminescence (PL)-based immunosensor was integrated into a microfluidic cell and tested for AFB1 detection. The mechanism of PL changes caused by AFB1 & Anti-AFB1 complex formation was analyzed and developed. The proposed approach enables the detection of AFB1 with the lowest concentration (LOD) of about 39 pg/ml, while the sensitivity range was evaluated as 0.1–20 ng/ml. The obtained values of LOD and sensitivity, as well as the simplicity of the detection method, make this approach a prospect for further application.

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19 Citations


Journal ArticleDOI: 10.1016/J.CHEMOSPHERE.2021.130676
01 Oct 2021-Chemosphere
Abstract: Modification of biochar for efficient removal of antibiotics from water could be a valuable approach in the environmental applications. In this study, a brown seaweed (Sargassum crassifolium) was pyrolyzed at 500 °C and the obtained biochar (SWBC) was modified with zeolite through the slurry method maintaining the ratio at 1:5 (zeolite: biochar) (SWBC-Z). Batch adsorption experiments were conducted to evaluate the adsorption tendency of SWBC and SWBC-Z for the removal of ciprofloxacin (CPX) from water via pH edge, kinetics, isotherm and thermodynamic experiments. The highest adsorption was in the pH range of 6.5–8, supported by the electrostatic attractions and hydrogen bonding with zwitterionic CPX. Experimental kinetics data was well-fitted to the pseudo-second-order and Elovich models (R2 of 0.992 and 0.976, respectively), while the Langmuir and Freundlich isotherm models best described the isotherm data (R2 of 0.954 and 0.976, respectively). The maximum adsorption capacity of 93.65 mg g−1 was recorded for the SWBC-Z. The models predicted chemisorption and physisorption interactions on the heterogenous biochar surface. Well-defined peaks of silanol groups in the FTIR spectrum of SWBC-Z and its electron microscopy confirmed the incorporation of zeolite minerals. Post adsorption FTIR analysis elucidated the changes in the surface functional groups of the SWBC-Z. Thermodynamic data revealed spontaneous and exothermic reaction between CPX and both the biochars. It was concluded that modification of pristine biochar with zeolite imparted greater surface area and additional active sites, which subsequently enhanced the overall CPX adsorption by the SWBC-Z.

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Topics: Freundlich equation (61%), Biochar (58%), Adsorption (57%) ... show more

4 Citations


Journal ArticleDOI: 10.1080/10934529.2021.1974267
Abstract: The objective of this research was to study an effective adsorbent for removing azithromycin (AZT) from industrial wastewater. AZT is an antibiotic used for many diseases remedy, but it is a pollutant to our environment; therefore, its residual should be removed from wastewater. The mesoporous SBA-15 silica as an efficient adsorbent was prepared by the hydrothermal method. The surface of mesoporous SBA-15 plays a significant role in the removal process; therefore, the characterization of the adsorbent was accomplished by several techniques. The batch system has been used, and the effect of four essential variables: pH (3-10), drug concentration (20-200 mg L-1), sorbent weight (0.2-2 g L-1), and temperature (20-40 °C) were investigated on the AZT removal efficiency by response surface methodology (RSM). The isotherm results were found to be in proper compliance with the isotherm model of Freundlich. In the kinetics part of this study, the experimental outcomes were fitted to the equation model of pseudo-second-order. The calculation of thermodynamic parameters shows that the removal process is spontaneous and endothermic. Upon the results, the vast surface area, the active functional groups, reusability, stability, and inexpensively make the mesoporous SBA-15 a suitable candidate for removal of AZT and similar antibiotics.

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Topics: Mesoporous silica (58%), Freundlich equation (56%), Mesoporous material (52%) ... show more

Journal ArticleDOI: 10.1016/J.CHEMOSPHERE.2021.131874
01 Jan 2022-Chemosphere
Abstract: Wastewater imposes a great threat to any ecosystem across the world, especially the aquatic one because of the different anthropogenic activities of human beings. The present study emphasizes the optimization of ecological parameters [pH, time (h) and temperature (°C)] employing Box-Behnken design (BBD) to achieve better bio-adsorption of a selected heavy metal [lead (Pb II)] from the wastewater through an extracellular polymeric substance (EPS) of a benthic fungus, Aspergillus penicillioides (F12) (MN210327). The relevant statistical analysis (ANOVA) has enabled to record of the optimized bio-adsorption (73.14 %) of lead (Pb II) by fungal EPS at pH (8.85) and temperature (32 °C) for a duration of 5.74 h. Besides that, at the concentration of 0.5 mg/L of EPS, the flocculating rate was noted to be highest (88.4 %) in kaolin clay and the 50 % emulsifying activity. This investigation has also opened up new vistas on the possibility of the development of an alternative method of eco-sustainable bioremediation of heavy metals by fungal EPS on an industrial scale.

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Open accessJournal ArticleDOI: 10.1186/S42834-021-00102-X
Diego Juela1, Mayra Vera1, Christian Cruzat1, Ximena Alvarez1  +1 moreInstitutions (1)
Abstract: Natural adsorbents are a good alternative to remove antibiotic residues from wastewater. In this study, the adsorption capacity of sulfamethoxazole (SMX) onto sugarcane bagasse (SB) and corn cob (CC) in a continuous fixed-bed was compared. Brunauer Emmett Teller, Fourier transform infrared (FTIR), Boehm titration, and point of zero charge (pHpzc) were used to characterize both adsorbents. The adsorption capacity (qe) and the removal percentage of SMX (% R) were investigated at different different flow rates (2, 5, and 7 mL min− 1) and adsorbent masses (4 and 6.4 g), and a constant initial concentration of 5 mg L− 1. The results of the characterization showed that SB has a morphology with more dispersed particles and a specific surface higher than CC (2.6 > 1.2 m2 g− 1). Boehm titration indicates that both the surface of SB and CC have a greater amount of acid groups, which is in agreement with FTIR and pHpzc results. The continuous fixed-bed experiments showed that % R and qe of SMX are higher with SB in all the tests. The highest qe and maximum % R was 0.24 mg g− 1 and 74% with SB, and 0.15 mg g− 1 and 65% using CC. In most cases, the qe of both adsorbents decreased with the increase of flow rate and bed height. An analysis suggests that hydrogen bonds could be the main factor favoring the SMX adsorption with SB. Finally, the intraparticle diffusion was the rate-controlling step, predominating the pore-volume diffusion resistance.

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Topics: Adsorption (53%)
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63 results found


Journal ArticleDOI: 10.1016/J.SCITOTENV.2012.04.028
Paola Verlicchi1, M. Al Aukidy1, E. Zambello1Institutions (1)
Abstract: This review focuses on 118 pharmaceuticals, belonging to seventeen different therapeutic classes, detected in raw urban wastewater and effluent from an activated sludge system, a usual treatment adopted for urban wastewaters worldwide prior to final discharge into surface water bodies. Data pertaining to 244 conventional activated sludge systems and 20 membrane biological reactors are analysed and the observed ranges of variability of each selected compound in their influent and effluent reported, with particular reference to the substances detected most frequently and in higher concentrations. A snapshot of the ability of these systems to remove such compounds is provided by comparing their global removal efficiencies for each substance. Where possible, the study then evaluates the average daily mass load of the majority of detected pharmaceuticals exiting the secondary treatment step. The final part of the review provides an assessment of the environmental risk posed by their presence in the secondary effluent by means of the risk quotient that is the ratio between the average pharmaceutical concentration measured in the secondary effluent and the predicted no-effect concentration. Finally, mass load rankings of the compounds under review are compared with those based on their risk level. This analysis shows that the highest amounts discharged through secondary effluent pertain to one antihypertensive, and several beta-blockers and analgesics/anti-inflammatories, while the highest risk is posed by antibiotics and several psychiatric drugs and analgesics/anti-inflammatories. These results are reported with a view to aiding scientists and administrators in planning measures aiming to reduce the impact of treated urban wastewater discharge into surface water bodies.

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Topics: Secondary treatment (57%), Effluent (55%), Wastewater (51%)

1,427 Citations



Journal ArticleDOI: 10.1016/0009-2509(62)87015-8
N. Wakao1, J. M. Smith1Institutions (1)
Abstract: A theory is proposed for predicting diffusion rates at constant pressure through bi-disperse porous media. The total rate is the sum of separate contributions for diffusion through macropores, micropores and a series path. To apply the theory requires a knowledge of the pore volume-pore radius distribution for the porous material. Experimental diffusion measurements are reported for five high-area alumina pellets of different densities made from the same Boehmite powder. The results show that for the least dense pellets macropore diffusion is dominant. In contrast the micropore contribution controls the diffusion rate in the most dense pellet. The theory predicts rates in good agreement with the data over the pressure range investigated, 1–12 atm. Comparison with other diffusion data is hindered by the lack of pore-volume-distribution information. However, such data are available for a silver catalyst and for a low-area alumina. For these different materials the theory also predicts reliable diffusion rates.

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749 Citations


Journal ArticleDOI: 10.1039/C4RA13734E
Shuying Dong1, Jinglan Feng1, Maohong Fan2, Maohong Fan3  +6 moreInstitutions (4)
28 Jan 2015-RSC Advances
Abstract: Visible light-responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources. This review summarizes the recent progress in the design and fabrication of visible light-responsive photocatalysts via various synthetic strategies, including the modification of traditional photocatalysts by doping, dye sensitization, or by forming a heterostructure, coupled with π-conjugated architecture, as well as the great efforts made within the exploration of novel visible light-responsive photocatalysts. Background information on the fundamentals of heterogeneous photocatalysis, the pathways of visible light-responsive photocatalysis, and the unique features of visible light-responsive photocatalysts are presented. The photocatalytic properties of the resulting visible light-responsive photocatalysts are also covered in relation to the water treatment, i.e., regarding the photocatalytic degradation of organic compounds and inorganic pollutants, as well as photocatalytic disinfection. Finally, this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.

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628 Citations


Journal ArticleDOI: 10.1016/J.CIS.2010.12.004
Abstract: It is necessary to establish the rate law of adsorbate-adsorbent interactions to understand the mechanism by which the solute accumulates on the surface of a solid and gets adsorbed to the surface. A number of theoretical models and equations are available for the purpose and the best fit of the experimental data to any of these models is interpreted as giving the appropriate kinetics for the adsorption process. There is a spate of publications during the last few years on adsorption of various metals and other contaminants on conventional and non-conventional adsorbents, and many have tried to work out the kinetics. This has resulted from the wide interest generated on using adsorption as a practical method for treating contaminated water. In this review, an attempt has been made to discuss the kinetics of adsorption of metal ions on inorganic solids on the basis of published reports. A variety of materials like clays and clay minerals, zeolites, silica gel, soil, activated alumina, inorganic polymer, inorganic oxides, fly ash, etc. have been considered as the adsorbents and cations and anions of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, and Zn as adsorbate have been covered in this review. The majority of the interactions have been divided into either pseudo first order or second order kinetics on the basis of the best fit obtained by various groups of workers, although second order kinetics has been found to be the most predominant one. The discussion under each category is carried out with respect to each type of metal ion separately. Application of models as given by the Elovich equation, intra-particle diffusion and liquid film diffusion has also been shown by many authors and these have also been reviewed. The time taken for attaining equilibrium in each case has been considered as a significant parameter and is discussed almost in all the cases. The values of the kinetic rate coefficients indicate the speed at which the metal ions adsorb on the materials and these are discussed in all available cases. The review aims to give a comprehensive picture on the studies of kinetics of adsorption during the last few years.

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591 Citations


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