Removal of Cd2+ from Water by Use of Super-Macroporous Cryogels and Comparison to Commercial Adsorbents

In this study amphoteric cryogels were synthesized by the use of free-radical co-polymerization of acrylate-based precursors (methacrylic acid and 2-acrylamido-2-methyl-1-propansulfonic acid) with allylamine at different ratios. The physico-chemical characteristics of the cryogels were examined using SEM/EDX, FT-IR, XPS and zeta potential measurements. The cryogels were tested toward Cd2+ removal from aqueous solutions at various pH and initial concentrations. Equilibrium studies revealed a maximum sorption capacity in the range of 132–249 mg/g. Leaching experiments indicated the stability of Cd2+ in the cryogel structure. Based on kinetics, equilibrium and characterization results, possible removal mechanisms are proposed, indicating a combination of ion exchange and complexation of Cd2+ with the cryogels’ surface functional groups. The cryogels were compared to commercially available adsorbents (zeolite Y and cation exchange resin) for the removal of Cd2+ from various water matrices (ultrapure water, tap water and river water) and the results showed that, under the experimental conditions used, the cryogels can be more effective adsorbents.

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Phosphate Removal Using Polyethylenimine Functionalized Silica-Based Materials

Sustainability ◽

10.3390/su13031502 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1502

Author(s):

Maria Xanthopoulou ◽

Dimitrios Giliopoulos ◽

Nikolaos Tzollas ◽

Konstantinos S. Triantafyllidis ◽

Margaritis Kostoglou ◽

...

Keyword(s):

Sorption Capacity ◽

Removal Rate ◽

Phosphate Concentration ◽

Phosphate Removal ◽

Equilibrium Studies ◽

Maximum Sorption Capacity ◽

Algae Blooms ◽

Maximum Sorption ◽

Phosphate Anions ◽

Adsorbent Dose

In water and wastewater, phosphate anions are considered critical contaminants because they cause algae blooms and eutrophication. The present work aims at studying the removal of phosphate anions from aqueous solutions using silica particles functionalized with polyethylenimine. The parameters affecting the adsorption process such as pH, initial concentration, adsorbent dose, and the presence of competitive anions, such as carbonate, nitrate, sulfate and chromate ions, were studied. Equilibrium studies were carried out to determine their sorption capacity and the rate of phosphate ions uptake. The adsorption isotherm data fitted well with the Langmuir and Sips model. The maximum sorption capacity was 41.1 mg/g at pH 5, which decreased slightly at pH 7. The efficiency of phosphate removal adsorption increased at lower pH values and by increasing the adsorbent dose. The maximum phosphate removal was 80% for pH 5 and decreased to 75% for pH 6, to 73% for pH 7 and to 70% for pH 8, for initial phosphate concentration at about 1 mg/L and for a dose of adsorbent 100 mg/L. The removal rate was increased with the increase of the adsorbent dose. For example, for initial phosphate concentration of 4 mg/L the removal rate increased from 40% to 80% by increasing the dose from 0.1 to 2.0 g/L at pH 7. The competitive anions adversely affected phosphate removal. Though they were also found to be removed to a certain extent. Their co-removal provided an adsorbent which might be very useful for treating waters with low-level multiple contaminant occurrence in natural or engineered aquatic systems.

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Synthesis, Characterization and its Application of Cu2+ Ion Imprinted Polymers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.512-515.2333 ◽

2012 ◽

Vol 512-515 ◽

pp. 2333-2338

Author(s):

Yong Feng Kang ◽

Yan Li ◽

Wu Ping Duan ◽

Jing Xie ◽

Jun Xia Kang

Keyword(s):

Competitive Sorption ◽

Functional Monomer ◽

Imprinted Polymer ◽

Imprinted Polymers ◽

Maximum Sorption Capacity ◽

Ion Imprinted ◽

Ion Imprinted Polymers ◽

Visible Spectra ◽

Maximum Sorption ◽

Ft Ir

Cu2+-imprinted polymers (Cu(II)–IIPs) were prepared by thermal precipitation polymerization method with Cu2+ion as the template, 1,4-dihydroxyanthraquinone (AQ) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker. In synthesis processes,The functional monomer AQ, there is only one functional groups that can selectively recognize Cu2+ ion, is set in highly cross-linked polymer net, not to form covalent-linkage with polymer net. The imprinted polymer particles were characterized by UV-visible spectra, FT-IR, scanning electron microscopy and colorimetry. The sorption and selectivity capacity of Cu(II)–IIPs for Cu2+ ion were studied．The results showed that the imprinted polymer had good affinity for Cu2+. The maximum sorption capacity was 11.4 mg/g．The sorption equilibrium time was 50 min and the optimum pH for quantitative copper retention was 7.0. Competitive sorption of Cu2+, Co2+, Zn2+, Mg2+, Ca2+ from their mixture was also studied in a batch system. The relatively selective factor of copper to other metal ions were greater than 1. The Cu(II)–IIPs could be repeatedly used with high selectivity and stability for Cu2+.This Cu(II)–IIPs has been successfully applied to the separation and determination of the trace Cu2+ in real water samples.

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Zinc-Containing Effluent Treatment Using Shewanella xiamenensis Biofilm Formed on Zeolite

Materials ◽

10.3390/ma14071760 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1760

Author(s):

Inga Zinicovscaia ◽

Nikita Yushin ◽

Dmitrii Grozdov ◽

Daler Abdusamadzoda ◽

Alexey Safonov ◽

...

Keyword(s):

Metal Removal ◽

Industrial Effluent ◽

Effluent Treatment ◽

Coefficient Of Determination ◽

Equilibrium Studies ◽

Maximum Sorption Capacity ◽

Maximum Sorption ◽

Pseudo Second Order ◽

Removal Of Metal Ions ◽

Ph Range

The sorption properties of Shewanella xiamenensis biofilm formed on zeolite (mineral-organic sorbent) as a sorbent have been investigated aiming to determine its suitability for complex zinc-containing effluent treatment. The optimum conditions for metal sorption from synthetic solutions were evaluated by changing the pH, zinc concentration, temperature, and time of sorption. The highest removal of metal ions was attained at pH range 3.0–6.0 within 60–150 min of sorbent-sorbate contact. The results obtained from the equilibrium studies were described using the Langmuir, Freundlich, and Temkin models. Maximum sorption capacity of the sorbent calculated from the Langmuir model changed from 3.4 to 6.5 mg/g. High coefficient of determination values calculated for pseudo-second-order and Elovich models indicate the predominant role of chemisorption in metal removal. Gibbs energy and ∆H° values point at the spontaneous and endothermic character of the sorption. The effect of pH and biosorbent mass on Zn(II) sorption from industrial effluent with an initial Zn(II) concentration of 52.8 mg/L was tested. Maximum removal of zinc ions (85%) was achieved at pH 6.0 by applying a two-step treatment system.

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Preparation and Characterization of a New Polymeric Multi-Layered Material Based K-Carrageenan and Alginate for Efficient Bio-Sorption of Methylene Blue Dye

Polymers ◽

10.3390/polym13030411 ◽

2021 ◽

Vol 13 (3) ◽

pp. 411

Author(s):

Chiraz Ammar ◽

Fahad M. Alminderej ◽

Yassine EL-Ghoul ◽

Mahjoub Jabli ◽

Md. Shafiquzzaman

Keyword(s):

Methylene Blue ◽

Sodium Alginate ◽

Blue Dye ◽

Experimental Conditions ◽

Virgin Sample ◽

Ft Ir ◽

Ir Analysis ◽

The Stability ◽

Cellulose Surface

The current study highlights a novel bio-sorbent design based on polyelectrolyte multi-layers (PEM) biopolymeric material. First layer was composed of sodium alginate and the second was constituted of citric acid and k-carrageenan. The PEM system was crosslinked to non-woven cellulosic textile material. Resulting materials were characterized using FT-IR, SEM, and thermal analysis (TGA and DTA). FT-IR analysis confirmed chemical interconnection of PEM bio-sorbent system. SEM features indicated that the microspaces between fibers were filled with layers of functionalizing polymers. PEM exhibited higher surface roughness compared to virgin sample. This modification of the surface morphology confirmed the stability and the effectiveness of the grafting method. Virgin cellulosic sample decomposed at 370 °C. However, PEM samples decomposed at 250 °C and 370 °C, which were attributed to the thermal decomposition of crosslinked sodium alginate and k-carrageenan and cellulose, respectively. The bio-sorbent performances were evaluated under different experimental conditions including pH, time, temperature, and initial dye concentration. The maximum adsorbed amounts of methylene blue are 124.4 mg/g and 522.4 mg/g for the untreated and grafted materials, respectively. The improvement in dye sorption evidenced the grafting of carboxylate and sulfonate groups onto cellulose surface. Adsorption process complied well with pseudo-first-order and Langmuir equations.

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Purification, characterization and effect of physico-chemical agents on the stability of ?-galactosidase from betel leaves

Journal of Bio-Science ◽

10.3329/jbs.v18i0.8785 ◽

1970 ◽

Vol 18 ◽

pp. 108-115

Author(s):

MS Shovon ◽

SCD Sharma ◽

N Roy

Keyword(s):

Gel Filtration ◽

Deae Cellulose ◽

Piper Betle ◽

Experimental Conditions ◽

Betel Leaf ◽

Sodium Phosphate Buffer ◽

Chemical Agents ◽

Physico Chemical ◽

The Stability

Context: β-galactosidase are present in a wide variety of organisms including plants, animals and microorganisms. Exploration of this enzyme from plant source will help to address the problems faced in the food and allied industries that look for enzymes with novel properties. Objectives: The aim of this study is to explore the purification, characterization and analysis of β-galactosidase from betel leaves. Materials and Methods: Aomal Bangla variety of betel leaf (Piper betle Linn.) was collected from betel vine. The column chromatographic method was done at 4°C using conventional method. The protein concentration was determined by UV-spectrophotometer at 280 nm. The activities of β-galactosidase were done by spectrophotometric method. All other reagents used in the study were of analytical grade. Unless specified, all the experimental conditions are maintained at 4°C. Results: After extraction of β-galactosidase from betel leaves, the crude enzyme was applied to DEAE-cellulose chromatography with sodium phosphate buffer (pH 7.0). The active fraction from DEAE-column chromatography was dialyzed with buffer and applied to CM-cellulose chromatography. The β-galactosidase activity from CM-cellulose chromatography was loaded to Sephadex G-75 Gel filtration chromatography. In this column, the enzyme β-galactosidase was eluted in a single peak. The homogeneity of purity was checked by disc gel electrophoresis and a single band was obtained. The optimum pH of β-GS-I, β-GS-II and β-GS-III were 3.5, 3.8 and 4.2, respectively. The optimum temperatures of the enzymes were 53, 51 and 56°C, respectively. Conclusion: The results obtained in this study suggest that three β-galactosidases namely β-GS-I, β-GS-II and β-GS-III were purified from betel leaves. This is the first report of purification and characterization of β-galactosidase from betel leaves. Keywords: Betel leaves; β-galactosidase; MW; characterisation; stability. DOI: http://dx.doi.org/10.3329/jbs.v18i0.8785 JBS 2010; 18(0): 108-115

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Release characteristics of an essential oil component encapsulated with cyclodextrin shell matrices

Current Drug Delivery ◽

10.2174/1567201817666200731164902 ◽

2020 ◽

Vol 17 ◽

Author(s):

Zhe Li ◽

Wangwen Wen ◽

Xulong Chen ◽

Lin Zhu ◽

Genjinsheng Cheng ◽

...

Keyword(s):

Particle Size ◽

Essential Oils ◽

Molecular Modelling ◽

Chemical Properties ◽

Order Kinetic ◽

First Order ◽

Binding Behavior ◽

Physico Chemical ◽

Ft Ir ◽

The Stability

Background: Essential oils are poor aqueous solubility and high volatility compounds. The encapsulation of essential oils with cyclodextrins (CDs) can protect them from the adverse environmental conditions and improve their stability. Therefore, increasing the functional capabilities of essential oils when they were used as additives in pharmaceutical and food systems. Additionally, the release of active compounds is an important issue. However, there were few studies about the effect of different CDs on the release of drugs after encapsulation. Therefore, the information on the study of release models is considerably limited. Objective: This study aimed to (i) characterize the physico-chemical properties and release behavior of myrcene encapsulated in the four different shell matrices of α-CD, β-CD, γ-CD and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), which were selected from the perspective of stability, and (ii) determine the release mechanism of myrcene in inclusion complexes (ICs). Methods: ICs of myrcene and four CDs were prepared by freeze-drying. The physico-chemical properties of ICs were fully characterized by laser diffraction particle size analyzer, scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FT-IR) and differential scanning calorimeter (DSC). The release behaviors of ICs at 50, 60, 70 and 80 °C were determined and described by zero-order or first-order kinetics with the Henderson-Pabis, Peppas, Avrami and Page mathematical models. Moreover, the possible binding modes of ICs were identified with molecular modelling technique. Results: Firstly, the structure of particle size distribution (PSD), FT-IR, DSC and SEM showed that (i) CDs could effectively encapsulate the myrcene molecules, and (ii) the release kinetics were well simulated by Avrami and Page models. Secondly, the release rates of the ICs experienced unsteady state in the early stage, and gradually became almost constants period after 20 hours. Except that the release of myrcene in γ-CD/myrcene belonged to the first-order kinetic, the release models of the remaining three ICs belonged to diffusion mode. Thirdly, the calculated binding energies of the optimized structures for α-CD/myrcene, β-CD/myrcene, γ-CD/myrcene, and HP-β-CD/myrcene ICs were −4.28, −3.82, −4.04, and −3.72 kcal/mol, respectively. Finally, the encapsulation of myrcene with α-CD and β-CD was preferable according to the stability and release characteristics. Conclusion: The encapsulation of myrcene was profoundly affected by the type of CDs, and the stability could be improved by complexation with suitable CDs. The binding behavior between guest and CD molecules, and the release profile of the guest molecules could be effectively explained by the kinetics parameters and molecular modelling. This study can provide an effective basis and guide for screening suitable shell matrices.

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Preparation of Nanocomposite Heteropoly Metalate Based Graphene Oxide: Insight into Cadmium Adsorption

Journal of Nanostructures ◽

10.18502/jns.v7i3.9 ◽

2017 ◽

Vol 7 (3) ◽

Cited By ~ 3

Author(s):

Hanieh Fakhri

Keyword(s):

Aqueous Solution ◽

Graphene Oxide ◽

Metal Ion ◽

Maximum Sorption Capacity ◽

Ion Removal ◽

Vis Spectroscopy ◽

Maximum Sorption ◽

Ft Ir ◽

Cadmium Adsorption ◽

Excellent Stability

We developed a facile strategy for preparation of heteropoly metalate/graphene oxide nanocomposite as a new ion exchanger for cadmium ion removal from aqueous solution. The synthesized nanocomposite was characterized by X-ray powder diffraction (XRD), UV-Vis spectroscopy, FT-IR spectroscopy and Raman spectroscopy. Our findings indicated that the combination of heteropoly metalate nanoparticles with graphene oxide results in an excellent performance for cadmium ions removal of aqueous solution. The experimental data demonstrated that the adsorption isotherm fitted well by Langmuir model with maximum sorption capacity of 47.85 mg/g. The removal behavior of this compound was evaluated by various parameters such as contact time, concentration of metal ion, pH of solution and temperature. In addition, the effect of interfering cations on the cadmium adsorption is investigated. Dubinin–Radushkevich model represented physical sorption occurred as bold mechanism that is confirmed by thermodynamic parameters. Also, the obtained data of the recycling experiment presented excellent stability after 4 consecutive cycles. This study indicated heteropoly metalate supported graphene oxide with good performance for removal of cadmium can be used for treating polluted solution by other heavy metal.

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Adsorption Capacities of Iron Hydroxide for Arsenate and Arsenite Removal from Water by Chemical Coagulation: Kinetics, Thermodynamics and Equilibrium Studies

Molecules ◽

10.3390/molecules26227046 ◽

2021 ◽

Vol 26 (22) ◽

pp. 7046

Author(s):

Muhammad Ali Inam ◽

Rizwan Khan ◽

Kang Hoon Lee ◽

Muhammad Akram ◽

Zameer Ahmed ◽

...

Keyword(s):

Iron Hydroxide ◽

Point Of Zero Charge ◽

Infrared Spectrometry ◽

Equilibrium Studies ◽

Chemical Coagulation ◽

Ζ Potential ◽

Maximum Sorption Capacity ◽

As Species ◽

Adsorption Affinity ◽

Ft Ir

Arsenic (As)-laden wastewater may pose a threat to biodiversity when released into soil and water bodies without treatment. The current study investigated the sorption properties of both As(III, V) oxyanions onto iron hydroxide (FHO) by chemical coagulation. The potential mechanisms were identified using the adsorption models, ζ-potential, X-ray diffraction (XRD) and Fourier Transform Infrared Spectrometry (FT-IR) analysis. The results indicate that the sorption kinetics of pentavalent and trivalent As species closely followed the pseudo-second-order model, and the adsorption rates of both toxicants were remarkably governed by pH as well as the quantity of FHO in suspension. Notably, the FHO formation was directly related to the amount of ferric chloride (FC) coagulant added in the solution. The sorption isotherm results show a better maximum sorption capacity for pentavalent As ions than trivalent species, with the same amount of FHO in the suspensions. The thermodynamic study suggests that the sorption process was spontaneously exothermic with increased randomness. The ζ-potential, FT-IR and XRD analyses confirm that a strong Fe-O bond with As(V) and the closeness of the surface potential of the bonded complex to the point of zero charge (pHzpc) resulted in the higher adsorption affinity of pentavalent As species than trivalent ions in most aquatic conditions. Moreover, the presence of sulfates, phosphates, and humic and salicylic acid significantly affected the As(III, V) sorption performance by altering the surface properties of Fe precipitates. The combined effect of charge neutralization, complexation, oxidation and multilayer chemisorption was identified as a major removal mechanism. These findings may provide some understanding regarding the fate, transport and adsorption properties onto FHO of As oxyanions in a complex water environment.

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Solid State Analysis and Theoretical Explorations on Polymorphic and Hydrate Forms of p-Hydroxybenzaldehyde Isonicotinichydrazone: Effect of Additives on Polymorphic Crystallization

10.26434/chemrxiv.6489425.v1 ◽

2018 ◽

Author(s):

Lincy Tom ◽

Victoria A. Smolenski ◽

Jerry P. Jasinski ◽

M.R. Prathapachandra Kurup

Keyword(s):

Hirshfeld Surface ◽

Framework Analysis ◽

Reaction Conditions ◽

Space Groups ◽

Effect Of Additives ◽

Ft Ir ◽

Packing Arrangement ◽

The Stability ◽

Ir And Raman ◽

Isonicotinic Hydrazide

The reaction of p-hydroxybenzaldehyde with an equimolar amount of isonicotinic hydrazide afforded two polymorphic and hydrate forms of p-hydroxybenzaldehyde isonicotinichydrazone (HBIH) by varying the experimental reaction conditions. The compounds are fully characterized by means of single crystal and powder diffraction methods, vibrational spectroscopy (FT-IR and Raman), thermal and elemental analysis. The compound crystallizes in three different forms in two different space groups, P21/c (form PA and PB) and Pbca (PC). The Hirshfeld surface analysis shows the differences in the relative contributions of intermolecular interactions to the total Hirshfeld surface area for the HBIH molecules. The calculated pairwise interaction energies (104-116 kJ/mol) can be related to the stability of the crystals. Energy framework analysis identifies the interaction hierarchy and their topology. The geometry and conformation of the three forms are essentially similar which differ only by packing arrangement.

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