Removal performance of faecal indicators by natural and silver-modified zeolites under dynamic batch experiments

2021 ◽  
Author(s):  
Vasiliki I. Syngouna ◽  
Ioannis Skandalis ◽  
Apostolos Vantarakis
Keyword(s):  
Waste Water Treatment ◽  
Silver Ions ◽  
Antimicrobial Effect ◽  
Natural Zeolites ◽  
Indicator Organisms ◽  
Batch Experiments ◽  
X Ray ◽  
Adsorption Capacities ◽  
And Control ◽  
Faecal Indicators

<p>The use of natural zeolites (NZs) in waste-water treatment plants is one of the oldest and most promising applications.  Modified natural zeolites (MZs) have shown improved ion exchange and adsorption capacities and have been extensively applied for the removal of pollutants (metal(loid) ions, ammonia etc) from aqueous solutions. However, MZs application in biological pollutants such as indicator organisms or pathogens has not been extensively explored. This study examines the antimicrobial effect of both natural Greek zeolite (NZ), with clinoptilolite content up to 85% (OLYMPOS SA), and modified Greek zeolite by incorporation with silver ions (Ag-MNZ) on the survival of two selected bacteria. The chosen organisms, <em>Escherichia coli </em>and <em>Enterococcus faecalis</em>, constitute indicators of fecal contamination in both soils and water. Scanning electron microscopy and energy dispersive X-ray detection (SEM-EDX) were used for the surface morphology and elemental composition of the NZ and Ag-MNZ samples, respectively. A series of dynamic batch experiments were conducted at constant room temperature (22°C) in order to examine the inactivation of the above bacteria by NZ and Ag-MNZ.  It was found that the Ag-MNZ resulted in much higher reduction of the bacterial numbers when compared to the NZ and control (absence of zeolites). Moreover, the reduction in the bacterial numbers was affected by NZ particle size with higher reduction observed for coarse (1-3 mm) than fine (0-1) NZ. Finally, the<em> E. faecalis</em> was found to be more resistant than <em>E.coli </em>to Ag-MNZ.</p>

scholarly journals Enhanced Adsorption Capacities of Fungicides Using Peanut Shell Biochar via Successive Chemical Modification with KMnO4 and KOH

Separations ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 52
Author(s):  
Yong-Gu Lee ◽  
Jaegwan Shin ◽  
Jinwoo Kwak ◽  
Sangwon Kim ◽  
Changgil Son ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Peanut Shell ◽  
Batch Experiments ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Treatment Processes ◽  
Adsorption Capacities ◽  
Isotherms And Thermodynamics ◽  
Effects Of Temperature ◽  
Enhanced Adsorption

This study explored the effects of peanut shell biochar (PSB) on the adsorption capacities of fungicides with and without successive chemical modifications, using KMnO4 and KOH (PSBOX-A), in order to provide a valuable understanding of their adsorption mechanisms and behaviors. To this end, the physicochemical properties of PSB and PSBOX-A were examined by using the Brunauer–Emmett–Teller method, Fourier transform infrared spectroscopy, and scanning electron microscopy with an energy dispersive X-ray spectrometer. The effects of temperature, ionic strength, and humic acids on the adsorption of fungicides, using PSB and PSBOX-A, were estimated through batch experiments. Furthermore, adsorption kinetics, isotherms, and thermodynamics were studied. The maximum adsorption capacities of fungicides by PSBOX-A were estimated to be more notable (Qmax of carbendazim = 531.2 μmol g−1, Qmax of pyrimethanil = 467.7 μmol g−1, and Qmax of tebuconazole = 495.1 μmol g−1) than PSB (Qmax of carbendazim = 92.6 μmol g−1, Qmax of pyrimethanil = 61.7 μmol g−1, and Qmax of tebuconazole = 66.7 μmol g−1). These findings suggest that successive chemical modification using KMnO4 and KOH could potentially be used to effectively fabricate PSB to remove fungicides in water-treatment processes.

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

Biocompatibility of Silver Nano Bio-conjugates from Vitis vinifera Seeds and its Major Component Resveratrol

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
R. Preethi ◽  
P. Padma
Keyword(s):  
Zeta Potential ◽  
Vitis Vinifera ◽  
Silver Ions ◽  
Seed Extract ◽  
Polydispersity Index ◽  
Potential Range ◽  
Visible Spectroscopy ◽  
Grape Seeds ◽  
X Ray ◽  
Uv Visible

The study focused on the green synthesis of silver nanobioconjugates (AgNPs) from phenolic-rich fruit source, Vitis vinifera seed extract and its major component phenolic, resveratrol respectively. Sunlight exposure for 20 minutes was the method of choice for the synthesis of AgNPs of the extract as well as the phenolic, resveratrol. The synthesized nanobioconjugates were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), Polydispersity index, Zeta potential and Fourier transform infrared spectroscopy (FTIR). The reduction of silver ions was confirmed by UV-visible spectroscopy with peaks at 440nm for both nanobioconjugates synthesized from seed extract and compound. The nanobioconjugates showed the spherical in shape with 14-35nm in size and crystalline in nature. The conjugates are well dispersed with 0.301 and 0.287 polydispersity index and the zeta potential range at -13.6 and -14.3mV for stability. The FTRI data proved that the components in grape seeds act as good reductants and stabilizers for the silver nanobioconjugate synthesis. All the synthesized nanobioconjugates exhibited steady and sustained release of the medicinal components conjugated, proving their druggability, and were biocompatible with human cells, demonstrating their safety. The findings of the study validate the anticancer properties of silver nanobioconjugates of Vitis vinifera and its active component resveratrol.

scholarly journals Combined Influence of Low-Grade Metakaolins and Natural Zeolite on Compressive Strength and Heavy Metal Adsorption of Geopolymers

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 486
Author(s):  
Alcina Johnson Sudagar ◽  
Slávka Andrejkovičová ◽  
Fernando Rocha ◽  
Carla Patinha ◽  
Maria R. Soares ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Compressive Strength ◽  
Natural Zeolite ◽  
Metal Adsorption ◽  
Low Grade ◽  
Heavy Metal Adsorption ◽  
Adsorption Model ◽  
X Ray ◽  
Adsorption Capacities

Metakaolins (MKs) prepared from low-grade kaolins located in the Alvarães (A) and Barqueiros (B) regions of Portugal were used as the aluminosilicate source to compare their effect on the compressive strength and heavy metal adsorption of geopolymers. Natural zeolite, an inexpensive, efficient adsorbent, was used as an additive in formulations to enhance geopolymers’ adsorption capacities and reduce MK utilization’s environmental footprint. Geopolymers were synthesized with the replacement of MK by zeolite up to 75 wt.% (A25, B25—25% MK 75% zeolite; A50, B50—50% MK 50% zeolite; A75, B75—75% MK 25% zeolite; A100, B100—100% MK). The molar ratios of SiO2/Al2O3 and Na2O/Al2O3 were kept at 1 to reduce the sodium silicate and sodium hydroxide environmental impact. Geopolymers’ crystallography was identified using X-ray diffraction analysis. The surface morphology was observed by scanning electron microscopy to understand the effect of zeolite incorporation. Chemical analysis using X-ray fluorescence spectroscopy and energy dispersive X-ray spectroscopy yielded information about the geopolymers’ Si/Al ratio. Compressive strength values of geopolymers obtained after 1, 14, and 28 days of curing indicate high strengths of geopolymers with 100% MK (A100—15.4 MPa; B100—32.46 MPa). Therefore, zeolite did not aid in the improvement of the compressive strength of both MK-based geopolymers. The heavy metal (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption tests exhibit relatively higher adsorption capacities of Barqueiros MK-based geopolymers for all the heavy metals except Cd2+. Moreover, zeolite positively influenced divalent cations’ adsorption on the geopolymers produced from Barqueiros MK as B75 exhibits the highest adsorption capacities, but such an influence is not observed for Alvarães MK-based geopolymers. The general trend of adsorption of the heavy metals of both MK-based geopolymers is Pb2+ > Cd2+ > Cu2+ > Zn2+ > Cr3+ when fitted by the Langmuir isotherm adsorption model. The MK and zeolite characteristics influence geopolymers’ structure, strength, and adsorption capacities.

scholarly journals Lifecycle Design of Disruptive SCADA Systems for Waste-Water Treatment Installations

2021 ◽  
Vol 13 (9) ◽  
pp. 4950
Author(s):  
Stelian Brad ◽  
Mircea Murar ◽  
Grigore Vlad ◽  
Emilia Brad ◽  
Mariuța Popanton
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
Value Added ◽  
Competitive Advantages ◽  
Major Focus ◽  
Scada System ◽  
Scada Systems ◽  
And Control ◽  
Lifecycle Design

Capacity to remotely monitor and control systems for waste-water treatment and to provide real time and trustworthy data of system’s behavior to various stakeholders is of high relevance. SCADA systems are used to undertake this job. SCADA solutions are usually conceptualized and designed with a major focus on technological integrability and functionality. Very little contributions are brought to optimize these systems with respect to a mix of target functions, especially considering a lifecycle perspective. In this paper, we propose a structured methodology for optimizing SCADA systems from a lifecycle perspective for the specific case of waste-water treatment units. The methodology embeds techniques for handling entropy in the design process and to assist engineers in designing effective solutions in a space with multiple constrains and conflicts. Evolutionary multiple optimization algorithms are used to handle this challenge. After the foundation of the theoretical model calibrated for the specific case of waste-water treatment units, a practical example illustrates its applicability. It is shown how the model can lead to a disruptive solution, which integrates cloud computing, IoT, and data analytics in the SCADA system, with some competitive advantages in terms of flexibility, cost effectiveness, and increased value added for both integrators and beneficiaries.

scholarly journals Adsorptive Removal of Cd, Cu, Ni and Mn from Environmental Samples Using Fe3O4-Zro2@APS Nanocomposite: Kinetic and Equilibrium Isotherm Studies

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3209
Author(s):  
Aphiwe Siyasanga Gugushe ◽  
Anele Mpupa ◽  
Tshimangadzo Saddam Munonde ◽  
Luthando Nyaba ◽  
Philiswa Nosizo Nomngongo
Keyword(s):  
Electron Microscopy ◽  
Magnetic Nanomaterials ◽  
Batch Mode ◽  
X Ray ◽  
Freundlich Isotherms ◽  
Adsorption Capacities ◽  
Transmission Electron ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Wastewater Samples

In this study, Fe3O4-ZrO2 functionalized with 3-aminopropyltriethoxysilane (Fe3O4-ZrO2@APS) nanocomposite was investigated as a nanoadsorbent for the removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions from aqueous solution and real samples in batch mode systems. The prepared magnetic nanomaterials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy/energy dispersion x-ray (SEM/EDX) Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Factors (such as adsorbent dose and sample pH) affecting the adsorption behavior of the removal process were studied using the response surface methodology. Under optimized condition, equilibrium data obtained were fitted into the Langmuir and Freundlich isotherms and the data fitted well with Langmuir isotherms. Langmuir adsorption capacities (mg/g) were found to be 113, 111, 128, and 123 mg/g for Cd, Cu, Ni and Mn, respectively. In addition, the adsorption kinetics was analyzed using five kinetic models, pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. The adsorbent was successfully applied for removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions in wastewater samples.

scholarly journals Bacterial cellulose films with ZnO nanoparticles and propolis extracts: Synergistic antimicrobial effect

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexandra Mocanu ◽  
Gabriela Isopencu ◽  
Cristina Busuioc ◽  
Oana-Maria Popa ◽  
Paul Dietrich ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Bacterial Cellulose ◽  
Food Packaging ◽  
Antimicrobial Effect ◽  
Gas Chromatography Mass Spectrometry ◽  
Trolox Equivalent Antioxidant Capacity ◽  
Zno Nps ◽  
X Ray ◽  
Cellulose Films ◽  
Trolox Equivalent

AbstractThis study aimed to obtain possible materials for future antimicrobial food packaging applications based on biodegradable bacterial cellulose (BC). BC is a fermentation product obtained by Gluconacetobacter xylinum using food or agricultural wastes as substrate. In this work we investigated the synergistic effect of zinc oxide nanoparticles (ZnO NPs) and propolis extracts deposited on BC. ZnO NPs were generated in the presence of ultrasounds directly on the surface of BC films. The BC-ZnO composites were further impregnated with ethanolic propolis extracts (EEP) with different concentrations.The composition of raw propolis and EEP were previously determined by gas-chromatography mass-spectrometry (GC-MS), while the antioxidant activity was evaluated by TEAC (Trolox equivalent antioxidant capacity). The analysis methods performed on BC-ZnO composites such as scanning electron microscopy (SEM), thermo-gravimetrically analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX) proved that ZnO NPs were formed and embedded in the whole structure of BC films. The BC-ZnO-propolis films were characterized by SEM and X-ray photon spectroscopy (XPS) in order to investigate the surface modifications. The antimicrobial synergistic effect of the BC-ZnO-propolis films were evaluated against Escherichia coli, Bacillus subtilis, and Candida albicans. The experimental results revealed that BC-ZnO had no influence on Gram-negative and eukaryotic cells.

Characterization of Silver Binding in Cryptomelane by X-ray Absorption Spectroscopy

1998 ◽  
Vol 524 ◽  
Author(s):  
R. Ravikumar ◽  
D. W. Fuerstenau ◽  
G. A. Waychunas
Keyword(s):  
Manganese Oxide ◽  
Silver Ions ◽  
Oxide Phase ◽  
Synthetic Sample ◽  
Temperature Spectrum ◽  
X Ray ◽  
Room Temperature Sample ◽  
X Ray Absorption ◽  
Temperature Sample

ABSTRACTUsing silver K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy, two different samples of silver-containing manganese oxide were analyzed in the fluorescence mode. For the first sample, silver ions from solution were sorbed onto one synthetic manganese oxide phase, namely cryptomelane (KxMn8O16, where l<x<2). The second sample was a silvermanganese oxide from Colorado. From the EXAFS analysis, silver was found to occupy two different sites in the synthetic sample. The natural samples from Colorado also exhibited a very similar coordination distances as the synthetic samples. In the low temperature spectrum of the synthetic sample at 10 K, the Ag-O peak was found to be missing and the amplitude of the Ag- Ag peak was approximately three times larger than the corresponding room temperature sample.

Adsorption of the harmful hormone ethinyl estradiol inside hydrophobic cavities of CTA+ intercalated montmorillonite

2016 ◽  
Vol 74 (3) ◽  
pp. 663-671 ◽  
Author(s):  
A. E. Burgos ◽  
Tatiana A. Ribeiro-Santos ◽  
Rochel M. Lago
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
High Efficiency ◽  
Interlayer Space ◽  
Ethinyl Estradiol ◽  
Significant Loss ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrophobic Cavity ◽  
Adsorption Capacities ◽  
Derivative Thermogravimetry

Hydrophobic cavities produced by cetyltrimethylammonium cation (CTA+) exchanged and trapped in the interlayer space of montmorillonite were used to remove the harmful hormone contaminant ethinyl estradiol (EE2) from water. X-ray diffraction, thermogravimetry/derivative thermogravimetry, elemental analysis (carbon, hydrogen, nitrogen), Fourier transform infrared, scanning electron microscopy/energy dispersive spectroscopy, Brunauer–Emmett–Teller and contact angle analyses showed that the intercalation of 9, 16 and 34 wt% CTA+ in the montmorillonite resulted in the d001 expansion from 1.37 to 1.58, 2.09 and 2.18 nm, respectively. EE2 adsorption experiments showed that the original clay montmorillonite does not remove EE2 from water whereas the intercalated composites showed high efficiency with adsorption capacities of 4.3, 8.8 and 7.3 mg g−1 for M9CTA+, M16CTA+ and M34CTA+, respectively. Moreover, experiments with montmorillonite simply impregnated with cetyltrimethylammonium bromide showed that the intercalation of CTA+ to form the hydrophobic cavity is very important for the adsorption properties. Simple solvent extraction can be used to remove the adsorbed EE2 without significant loss of CTA+, which allows the recovery and reuse of the adsorbent for at least five times.

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