scholarly journals α-amylase Immobilized Composite Cryogels: Some Studies on Kinetic and Adsorption Factors

2021 ◽  
Author(s):  
Ömür Acet ◽  
Tülden İnanan ◽  
Burcu Önal Acet ◽  
Emrah Dikici ◽  
Mehmet Odabaşı
Keyword(s):  
Low Cost ◽  
High Adsorption ◽  
X Ray ◽  
Column System ◽  
Xrf Scanning ◽  
Optimum Ph ◽  
Effects Of Ph ◽  
Characterization Studies ◽  
Fluorescence Spectrometer ◽  
Important Enzyme

Abstract Stability of enzymes is significant factor for their industrial feasibility. α–amylase is an important enzyme for some industries i.e., textile, food, paper and pharmaceutics.. Pumice particles (PPa) are non-toxic, natural, low-cost alternative adsorbents with high adsorption capacity. In this study, Cu2+ ions were attached onto pumice particles (Cu2+-APPa). Then, Cu2+-APPa embedded composite cryogel was synthesized (Cu2+-APPaC) via polymerization of gel-forming agents at minus temperatures. Characterization studies of the Cu2+-APPaC cryogel column was performed by X-ray fluorescence spectrometer (XRF), scanning electron microscopy (SEM), and Brunauer, Emmett, Teller (BET) apparatus. The experiments were carried out in a continuous column system. α–amylase was adsorbed onto Cu2+-APPaC cryogel with maximum amount of 858.7 mg/g particles at pH 4.0. Effects of pH and temperature on the activity profiles of the free and the immobilized α–amylase were investigated, and results indicate that immobilization did not alter the optimum pH and temperature values. kcat value of the immobilized α–amylase is higher than that of the free α–amylase while KM value increases by immobilization. Storage and operational stabilities of the free and the immobilized α–amylase were determined for 35 days and for 20 runs, respectively.

scholarly journals Adsorption capability of brewed tea waste in waters containing toxic lead(II), cadmium (II), nickel (II), and zinc(II) heavy metal ions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hakan Çelebi ◽  
Gülden Gök ◽  
Oğuzhan Gök
Keyword(s):  
Heavy Metals ◽  
Adsorption Process ◽  
Low Cost ◽  
Adsorption Capacities ◽  
Tea Waste ◽  
Optimum Ph ◽  
Effects Of Ph ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Adsorption Capability

Abstract Recently, the search for low-cost eco-friendly adsorbents has become one of the main objectives of researchers. The aim of this study was to test the removal of four heavy metals, namely lead (Pb), zinc (Zn), nickel (Ni) and cadmium (Cd), from a simulated watery solution using brewed tea waste as a potentially suitable adsorbent. The effects of pH levels (2.0–6.0), adsorbent amount (0.1–5.0 g), contact times (1–150 min.) were examined throughout the adsorption process. The results of the experiments showed that the heavy metals elimination yields had an inverse relationship with pH and a linear relationship between the other parameters. The optimum pH for the removal of the heavy metals was between 4.0 and 5.0 in the case of the brewed tea waste. Equilibrium times of 2, 10, 30 and 5 min were required for the adsorption of Pb, Zn, Ni, Cd onto Camellia sinensis, respectively. Based on the results of this study it can be said that brewed tea waste has a high potential to remove heavy metals from aqueous solutions. The maximum adsorption capacities were calculated as 1.197, 1.457, 1.163 and 2.468 mg/g, for Pb, Zn, Ni and Cd, respectively, by fitting the equilibrium data to the Langmuir isotherm model.

scholarly journals Multiple linear regression and random forest to predict and map soil properties using data from portable X-ray fluorescence spectrometer (pXRF)

2017 ◽  
Vol 41 (6) ◽  
pp. 648-664 ◽  
Author(s):  
Sérgio Henrique Godinho Silva ◽  
Anita Fernanda dos Santos Teixeira ◽  
Michele Duarte de Menezes ◽  
Luiz Roberto Guimarães Guilherme ◽  
Fatima Maria de Souza Moreira ◽  
...  
Keyword(s):  
Random Forest ◽  
Linear Regression ◽  
Soil Properties ◽  
Multiple Linear Regression ◽  
Low Cost ◽  
High Accuracy ◽  
Important Variable ◽  
X Ray ◽  
Element Contents ◽  
Fluorescence Spectrometer

ABSTRACT Determination of soil properties helps in the correct management of soil fertility. The portable X-ray fluorescence spectrometer (pXRF) has been recently adopted to determine total chemical element contents in soils, allowing soil property inferences. However, these studies are still scarce in Brazil and other countries. The objectives of this work were to predict soil properties using pXRF data, comparing stepwise multiple linear regression (SMLR) and random forest (RF) methods, as well as mapping and validating soil properties. 120 soil samples were collected at three depths and submitted to laboratory analyses. pXRF was used in the samples and total element contents were determined. From pXRF data, SMLR and RF were used to predict soil laboratory results, reflecting soil properties, and the models were validated. The best method was used to spatialize soil properties. Using SMLR, models had high values of R² (≥0.8), however the highest accuracy was obtained in RF modeling. Exchangeable Ca, Al, Mg, potential and effective cation exchange capacity, soil organic matter, pH, and base saturation had adequate adjustment and accurate predictions with RF. Eight out of the 10 soil properties predicted by RF using pXRF data had CaO as the most important variable helping predictions, followed by P2O5, Zn and Cr. Maps generated using RF from pXRF data had high accuracy for six soil properties, reaching R2 up to 0.83. pXRF in association with RF can be used to predict soil properties with high accuracy at low cost and time, besides providing variables aiding digital soil mapping.

Preparation and Characterization of Citric Acid Modified Marigold Dregs Biosorbents

2011 ◽  
Vol 236-238 ◽  
pp. 895-898
Author(s):  
Yi Wang ◽  
Ting Zhang ◽  
Kun Jie Wang ◽  
De Yi Zhang
Keyword(s):  
Citric Acid ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Infrared Emission ◽  
Hydroxyl Groups ◽  
High Adsorption ◽  
Adsorption Ability ◽  
X Ray ◽  
Adsorption Quantity

The objectives of this study were to convert marigold dregs to a cationic metal ions and dye adsorbent and further to investigate the potential of using the adsorbent for the removal of copper(Ⅱ) and methylene blue (MB) from effluents. The base washed marigold dregs and citric acid (CA) modified marigold dregs (MMD) were prepared and the structure were investigated by fourier transform infrared, emission scanning electron microscope and X-ray photoelectron spectroscopy. The results show that the modification did not significantly change the morphology of the dregs surface structure but the esterificated reaction could increase the carboxyl groups and hydroxyl groups on the surface of the adsorbent. The adsorption ability are also evaluated by MB and copper(Ⅱ) and the results show the MMD is an excellent adsorbent. Due to the high adsorption quantity, it may be used as a low cost alternate adsorbent for the elimination of metal and dye ions form effluents.

Characterization and application of wood-ZrO2 sorbent for simultaneous removal of chromium (III) and chromium (VI) from binary mixture

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nena Velinov ◽  
Milica Petrović ◽  
Miljana Radović Vučić ◽  
Miloš Kostić ◽  
Jelena Mitrović ◽  
...  
Keyword(s):  
Low Cost ◽  
Sorption Process ◽  
Simultaneous Removal ◽  
Wood Residue ◽  
X Ray ◽  
Binary Component ◽  
Chromium Vi ◽  
Component Solution ◽  
Furniture Manufacturing ◽  
Effects Of Ph

Abstract A new woodchips-ZrO2 biosorbent (W-ZrO2) was synthesized using wood residue material generated from the oak tree (Quercus robur) during furniture manufacturing. Biosorbent was tested for the simultaneous removal of both chromium (Cr) ions: Cr(III) and Cr(VI), in the binary component solution. Biosorbent characterization was performed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction analysis (XRD). To define optimal process parameters for simultaneous removal of both Cr species, effects of pH, temperature, sorbent dosage and Cr ions concentration on the sorption process were investigated. Sorption of Cr ions onto W-ZrO2 was highly pH-dependent. Optimal pH for simultaneous removal of both Cr(III) and Cr(VI) ions is 4.0 with removal efficiency over 99.5 % in both cases. Equilibrium experimental results are the best fitted by the Langmuir sorption isotherm model. The maximal sorption capacities of the biosorbent for simultaneous removal of Cr(III) and Cr(VI) ions in binary-component system are 16.18 and 83.52 mg g−1, respectively. The present study shows that using wood residue material to produce a low-cost sorbent can effectively decrease the water pollution simultaneously removing both chromium species from water and also reduce wood waste and increase reuse/recycling options.

Synthesis, Characterization and Luminescence Properties of Rod-Like LaPO4:Eu3+ Nanostructures

2016 ◽  
Vol 16 (4) ◽  
pp. 4012-4015 ◽  
Author(s):  
Li Peng ◽  
Liu Yun ◽  
Shi Xiaolei ◽  
Guo Yaxin ◽  
Zhu Gangqiang
Keyword(s):  
Large Scale ◽  
Room Temperature ◽  
Emission Spectra ◽  
Luminescence Properties ◽  
X Ray ◽  
Sem And Tem ◽  
Effects Of Ph ◽  
Composition Structure ◽  
20 Nm ◽  
Fluorescence Spectrometer

Large-scale, rod-like nanostructures of LaPO4:Eu3+ phosphors were synthesized using a simple hydrothermal method. The phase composition, structure and morphology of the final products were characterized by XRD, FE-SEM and TEM. Highly crystalline material was obtained as confirmed by X-ray powder diffraction measurements. The FE-SEM and TEM observations indicate that the obtained LaPO4:Eu3+ nanorods have a diameter of about 10–20 nm, and a length of about 100–600 nm. Meanwhile, the excitation and emission spectra of the products at room temperature were measured using a fluorescence spectrometer. The effects of pH and Eu3+-doping on the morphology and luminescence properties of the as-prepared powders were investigated. The photoluminescence (PL) spectra show that the emission intensity of the LaPO4:Eu3+ phosphors improved with increases in concentrations of Eu3+ from 3 mol% to 14 mol%, and then decreased for higher concentrations.

Conditions affecting oxide quantification in unknown tropical soils via handheld X-ray fluorescence spectrometer

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 648 ◽  
Author(s):  
M. L. T. Santana ◽  
B. T. Ribeiro ◽  
S. H. G. Silva ◽  
G. C. Poggere ◽  
L. R. G. Guilherme ◽  
...  
Keyword(s):  
Soil Profile ◽  
Low Cost ◽  
Tropical Soils ◽  
Soil Samples ◽  
Soil Matrix ◽  
X Ray ◽  
Plastic Bags ◽  
Colour System ◽  
Fluorescence Spectrometer

Soil chemical characterisation has been accurately performed worldwide using portable X-ray fluorescence (pXRF), contributing to fast, low-cost and environmentally-friendly soil analyses. However, many factors can influence the pXRF performance. Thus, this work was carried out to assess the oxides (SiO2, Al2O3, Fe2O3, TiO2 and P2O5) in tropical soils via pXRF, evaluating the effects of soil packing prior to analysis and the soil matrix. The packing of soil samples was performed using X-ray thin-film and common, low-cost plastic bags. Different soil matrices were obtained by grouping of samples according to the Munsell colour system. The obtained results were compared with a conventional method employed for the determination of soil oxides. In addition, the pXRF measurements made on either sieved soil samples or directly on the soil profile were compared. The P2O5 content was below the detection limit of pXRF (0.05 g kg−1). The Fe2O3 and TiO2 contents of several tropical soils were accurately determined via pXRF using air-dried and sieved samples. This result was not observed for SiO2 and Al2O3. For Fe2O3, a good correlation (R2 = 0.91) was obtained between pXRF measurements made on sieved soil samples and directly on the soil profile. The packing of soil samples using plastic bags did not negatively influence the pXRF performance.

scholarly journals Use of Lignite as a Low-Cost Material for Cadmium and Copper Removal from Aqueous Solutions: Assessment of Adsorption Characteristics and Exploration of Involved Mechanisms

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 164
Author(s):  
Salah Jellali ◽  
Ahmed Amine Azzaz ◽  
Mejdi Jeguirim ◽  
Helmi Hamdi ◽  
Ammar Mlayah
Keyword(s):  
Aqueous Solutions ◽  
Low Cost ◽  
X Ray Diffraction ◽  
High Adsorption ◽  
Experimental Conditions ◽  
X Ray ◽  
Ph Values ◽  
Adsorption Capacities ◽  
Or Groups ◽  
Pseudo Second Order

Lignite, as an available and low-cost material, was tested for cadmium (Cd) and copper (Cu) removal from aqueous solutions under various static experimental conditions. Experimental results showed that the removal efficiency of both metals was improved by increasing their initial concentrations, adsorbent dosage and aqueous pH values. The adsorption kinetic was very rapid for Cd since about 78% of the totally adsorbed amounts were removed after a contact time of only 1 min. For Cd and Cu, the kinetic and isothermal data were well fitted with pseudo-second order and Freundlich models, respectively, which suggests that Cd/Cu removal by lignite occurs heterogeneously on multilayers surfaces. The maximum Langmuir’s adsorption capacities of Cd and Cu were assessed to 38.0 and 21.4 mg g−1 and are relatively important compared to some other lignites and raw natural materials. Results of proximate, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD) showed that the removal of these metals occurs most likely through a combination of cation exchange and complexation with specific functional groups. The relatively high adsorption capacity of the used lignite promotes its future use as a low cost material for Cd and Cu removal from effluents, and possibly for other heavy metals or groups of pollutants.

X-Ray Fluorescence Spectrometer with Geometry of Grazing Incidence X-ray Radiation

2012 ◽  
Vol 1 (2) ◽  
pp. 78-82
Author(s):  
N.M. Novikovskii ◽  
◽  
V.M. Raznomazov ◽  
V.O. Ponomarenko ◽  
D.A. Sarychev ◽  
...  
Keyword(s):  
Grazing Incidence ◽  
X Ray ◽  
Fluorescence Spectrometer

scholarly journals Use of WetSEM® capsules for convenient multimodal scanning electron microscopy, energy dispersive X-ray analysis, and micro Raman spectroscopy characterisation of technetium oxides

2021 ◽  
Author(s):  
D. J. Bailey ◽  
M. C. Stennett ◽  
J. Heo ◽  
N. C. Hyatt
Keyword(s):  
Raman Spectroscopy ◽  
Low Cost ◽  
Powder Materials ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Hazard And Risk ◽  
Sem Imaging ◽  
General User ◽  
532 Nm

AbstractSEM–EDX and Raman spectroscopy analysis of radioactive compounds is often restricted to dedicated instrumentation, within radiological working areas, to manage the hazard and risk of contamination. Here, we demonstrate application of WetSEM® capsules for containment of technetium powder materials, enabling routine multimodal characterisation with general user instrumentation, outside of a controlled radiological working area. The electron transparent membrane of WetSEM® capsules enables SEM imaging of submicron non-conducting technetium powders and acquisition of Tc Lα X-ray emission, using a low cost desktop SEM–EDX system, as well as acquisition of good quality μ-Raman spectra using a 532 nm laser.

scholarly journals Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1786
Author(s):  
Carla Queirós ◽  
Chen Sun ◽  
Ana M. G. Silva ◽  
Baltazar de Castro ◽  
Juan Cabanillas-Gonzalez ◽  
...  
Keyword(s):  
Water Content ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Low Cost ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

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