Adsorption Properties of the Macro/Nano-Clay in Crystal Violet Solution

2015 ◽  
Vol 814 ◽  
pp. 488-497
Author(s):  
Hai Hui Bai ◽  
Ran Jin ◽  
Qing Song Zhang ◽  
Guo Zheng ◽  
Di Guo
Keyword(s):  
Ph Value ◽  
Magnesium Silicate ◽  
Exchange Effect ◽  
Adsorption Mechanisms ◽  
Root Cause ◽  
Crystal Violet Solution ◽  
Nano Clay ◽  
Ph Conditions ◽  
Neutral Conditions ◽  
Adsorption Phenomena

In this study, different appearances, structures and morphologies of macro-clay G105-Polymer grade montmorillonite (PMMT) and nanoclay Lithium magnesium silicate (LMSH) were compared and analyzed, which were used in different conditions of non-adsorption and adsorption of crystal violent (CV). Adsorption kinetics and properties of the macro/nanoclay in CV solution were studied, and adsorption time, dye concentration and environmental pH were the main factors on the inspection in this work. The adsorption mechanisms of the macro-/nanoclay on CV were investigated. The results showed that adsorption actions of PMMT and LMSH on CV were some similar, such as time-dependent, linear growth of adsorbed CV amount with increasing CV concentration, adsorption capacity of macro-/nanoclay declined firstly and then increased in 10mg/L CV solution along with increasing pH value. But the adsorption differences in two systems of PMMT-CV and LMSH-CV were obvious. Adsorption behavior of LMSH-CV system showed two adsorption phenomena. Under neutral conditions, adsorbed CV amount in 0.5g LMSH was 1.69 times that of PMMT. Adsorption amount of LMSH was more significant to be affected by dye concentration and pH conditions. The research achievements further showed that adsorption mechanism was the root cause of the following difference. The adsorption of PMMT-CV relied mainly on iron-exchange effect of layers replaceable cations and surface adsorbed ions with CV cations, while the significant adsorption of LMSH-CV was mainly due to the electrostatic interaction from layers negative charge distribution and CV cationic properties in the solution, partly surface ions exchanges also existed in the adsorption process of LMSH-CV.

scholarly journals Change in the stability of goat milk and cow milk due to pH and heat

2021 ◽  
Vol 233 ◽  
pp. 02046
Author(s):  
Xiaoxue Fan ◽  
Ming Cheng ◽  
Xiaoning Zhang ◽  
Cunfang Wang ◽  
Hua Jiang
Keyword(s):  
Thermal Stability ◽  
Milk Production ◽  
Ph Value ◽  
Goat Milk ◽  
Cow Milk ◽  
Type B ◽  
Fresh Milk ◽  
Ph Conditions ◽  
The Stability ◽  
Thermal Stability Of

This paper aimed to evaluate the changes in the thermal stability of goat milk, cow milk and homogenized milk under different pH conditions. The results showed that goat milk was of type B milk, and the thermal stability were positively correlated with the pH value. But cow milk was of type A milk, the most stable pH of fresh milk was 6.9, while it was 6.7 for homogenized cow milk. Compared with cow milk, the acidification of goat milk was stronger due to heat. Therefore, in the process of milk production, the germicidal heating conditions of two different milk sources should be determined according to their thermal stability.

scholarly journals Biodegradation of Microplastic Derived from Poly(ethylene terephthalate) with Bacterial Whole-Cell Biocatalysts

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1326 ◽  
Author(s):  
Jixian Gong ◽  
Tongtong Kong ◽  
Yuqiang Li ◽  
Qiujin Li ◽  
Zheng Li ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
Feedback Inhibition ◽  
Culture Solution ◽  
The Novel ◽  
Whole Cell ◽  
Novel Approach ◽  
Poly Ethylene Terephthalate ◽  
Ph Conditions ◽  
Poly Ethylene ◽  
Neutral Conditions

At present, the pollution of microplastic directly threatens ecology, food safety and even human health. Polyethylene terephthalate (PET) is one of the most common of microplastics. In this study, the micro-size PET particles were employed as analog of microplastic. The engineered strain, which can growth with PET as sole carbon source, was used as biocatalyst for biodegradation of PET particles. A combinatorial processing based on whole-cell biocatalysts was constructed for biodegradation of PET. Compared with enzymes, the products can be used by strain growth and do not accumulated in culture solution. Thus, feedback inhibition of products can be avoided. When PET was treated with the alkaline strain under high pH conditions, the product concentration was higher and the size of PET particles decreased dramatically than that of the biocatalyst under neutral conditions. This shows that the method of combined processing of alkali and organisms is more efficient for biodegradation of PET. The novel approach of combinatorial processing of PET based on whole-cell biocatalysis provides an attractive avenue for the biodegradation of micplastics.

scholarly journals Site-selective remote C(sp3)–H heteroarylation of amides via organic photoredox catalysis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Hui Chen ◽  
Wenjing Fan ◽  
Xiang-Ai Yuan ◽  
Shouyun Yu
Keyword(s):  
Hydrogen Atom ◽  
Room Temperature ◽  
Ph Value ◽  
Metal Free ◽  
Selective Functionalization ◽  
Site Selectivity ◽  
Hydrogen Atom Transfers ◽  
Site Selective ◽  
Neutral Conditions ◽  
Potential Complement

Abstract Radical translocation processes triggered by nitrogen-centered radicals (NCRs), such as 1,5-hydrogen atom transfers (1,5-HAT), demonstrated by the well-established Hofmann-Löffler-Freytag (HLF) reaction, provide an attractive approach for the controllable and selective functionalization of remote inert C(sp3)–H bonds. Here we report an amidyl radical-triggered site-selective remote C(sp3)–H heteroarylation of amides under organic photoredox conditions. This approach provides a mild and highly regioselective reaction affording remote C(sp3)–H heteroarylated amides at room temperature under transition-metal free, weakly basic, and redox-neutral conditions. Non-prefunctionalized heteroarenes, such as purines, thiazolopyridines, benzoxazole, benzothiazoles, benzothiophene, benzofuran, thiazoles and quinoxalines, can be alkylated directly. Sequential and orthogonal C–H functionalization of different heteroarenes by taking advantage pH value or polarity of radicals has also been achieved. DFT calculations explain and can predict the site-selectivity and reactivity of this reaction. This strategy expands the scope of the Minisci reaction and serves as its alternative and potential complement.

scholarly journals A new insight into the restriction of Cr(VI) removal performance of activated carbon under neutral pH condition

2021 ◽  
Author(s):  
Yi Fang ◽  
Ke Yang ◽  
Yipeng Zhang ◽  
Changsheng Peng ◽  
Aurora Robledo-Cabrera ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Photoelectron Spectroscopy ◽  
Toxic Heavy Metal ◽  
X Ray ◽  
Neutral Ph ◽  
Removal Capacity ◽  
Ph Conditions ◽  
Neutral Conditions ◽  
The Impact

Abstract Activated carbon has been widely used to remove hazardous Cr(VI), however, the impact of Cr2O3 precipitate on gradually declined removal ability as pH increased has received little attention. Herein, to investigate the effect of Cr2O3, SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis) coupling elements mapping of chromium loaded powder activated carbon (PAC) revealed that a chromium layer was formed on the PAC exterior after being treated with Cr(VI) at pH 7. XPS (X-ray photoelectron spectroscopy) study confirmed that 69.93% and 39.91% Cr2O3 precipitated on the PAC surface at pH 7 and pH 3, respectively, corresponding to 17.77 mg/g and 20 mg/g removal capacity. Exhausted PAC had a removal efficiency of 92.43% after Cr2O3 being washed by H2SO4 solution, which was much higher than the removal efficiency of 51.27 % after NaOH washing. This further verified the intrinsically developed Cr2O3 precipitate on PAC under neutral conditions limited the durability of PAC as an adsorbent. Consecutive elution assessments confirmed that adsorption and reduction ability both declined as pH increased. Raman spectroscopy and C 1s spectra of materials demonstrated two distinct Cr(VI) removal mechanisms under pH 3 and pH 7. In conclusion, the exhausted AC after Cr(VI) adsorption can be rejuvenated after the surface coated Cr2O3 being washed by the acid solution which can expand the longevity of AC and recover Cr(III). HIGHLIGHT In this work, we scrutinized the mechanism of poor removal capacity of commercial activated carbon on toxic heavy metal Cr(VI) under neutral pH conditions. Differing from the most accepted view that electrostatic repulsion is the main consideration, our study suggested that the relatively more Cr2O3 precipitate on the surface of activated carbon under higher pH led to the low Cr(VI) sequestration capability.

A membrane-based electrochemical flow reactor for generation of ferrates at near neutral pH conditions

2019 ◽  
Vol 4 (6) ◽  
pp. 1116-1125 ◽  
Author(s):  
Macarena A. Cataldo-Hernández ◽  
Arman Bonakdarpour ◽  
Joseph T. English ◽  
Madjid Mohseni ◽  
David P. Wilkinson
Keyword(s):  
Flow Reactor ◽  
Boron Doped Diamond ◽  
Neutral Ph ◽  
Boron Doped ◽  
Ph Conditions ◽  
Reactor Operating ◽  
Neutral Conditions

We report the electrosynthesis of Fe(vi) in a flow reactor operating in batch recirculation mode at neutral conditions using boron doped diamond (BDD) and Fe(iii).

scholarly journals Zinc adsorption in highly weathered soils

2008 ◽  
Vol 43 (1) ◽  
pp. 131-139 ◽  
Author(s):  
José Carlos Casagrande ◽  
Marcio Roberto Soares ◽  
Ernesto Rinaldi Mouta
Keyword(s):  
Ionic Strength ◽  
Ph Value ◽  
Batch Adsorption ◽  
Adsorption Mechanisms ◽  
Ionic Strength Effect ◽  
Ph Values ◽  
Effects Of Ph ◽  
Ph Range ◽  
Highly Weathered Soils ◽  
Zinc Adsorption

The objective of this work was to assess the effects of pH and ionic strength upon zinc adsorption, in three highly weathered variable charge soils. Adsorption isotherms were elaborated from batch adsorption experiments, with increasing Zn concentrations (0-80 mg L-1), and adsorption envelopes were constructed through soil samples reactions with 0.01, 0.1 and 1 mol L-1 Ca(NO3)2 solutions containing 5 mg L-1 of Zn, with an increasing pH value from 3 to 8. Driving force of reaction was quantified by Gibbs free energy and separation factor. Isotherms were C-, H- and L-type and experimental results were fitted to nonlinear Langmuir model. Maximum adsorption ranged from 59-810 mg kg-1, and Zn affinity was greater in subsoil (0.13-0.81 L kg-1) than in the topsoil samples (0.01-0.34 L kg-1). Zinc adsorption was favorable and spontaneous, and showed sharply increase (20-90%) in the 4-6 pH range. No effect of ionic strength was observed at pH values below 5, because specific adsorption mechanisms predominated in the 3-5 pH range. Above pH 5, and in subsoil samples, Zn was adsorbed by electrostatic mechanisms, since ionic strength effect was observed. Despite depth and ionic strength effects, Zn adsorption depends mainly on the pH.

Characterisation of Norway spruce hemicelluloses extracted by pressurised hot-water extraction (ASE) in the presence of sodium bicarbonate

Holzforschung ◽  
2011 ◽  
Vol 65 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Tao Song ◽  
Andrey Pranovich ◽  
Bjarne Holmbom
Keyword(s):  
Sodium Bicarbonate ◽  
Norway Spruce ◽  
Ph Value ◽  
Hot Water ◽  
Water Extraction ◽  
Extraction Time ◽  
Plain Water ◽  
Hot Water Extraction ◽  
Ph Conditions ◽  
Optimal Ph

Abstract Ground spruce sapwood was extracted with pressurised hot water with addition of different amounts of sodium bicarbonate (NaHCO3) to find optimal pH conditions for extraction of hemicelluloses, especially of galactoglucomannans (GGMs). The extractions were carried out in an accelerated solvent extractor (ASE) at 170°C. When extraction was carried out with 2.5 mM NaHCO3 during 60–100 min extraction time (end-pH 3.9), more than 60% of the total extracted substances were hemicellulose-derived carbohydrates. Under these conditions, approximately 80% of the extracted carbohydrates were from GGMs (13% b.o. wood). At higher concentrations of NaHCO3, the yield of carbohydrates, especially those derived from GGMs, decreased. Hydrolytic depolymerisation of hemicelluloses occurring during extraction with plain water was largely inhibited in the presence of 2.5–5 mM NaHCO3. The hydrolytic deacetylation of GGM was diminished at low NaHCO3 concentrations but increased dramatically at higher NaHCO3 concentrations. It can be concluded that 2.5–5 mM NaHCO3 giving an end-pH value of 4 is better for GGM isolation than plain water.

scholarly journals Separation at neutral pH value of 32P-labelled proteins in a membrane preparation from ox brain. Partial characterization of a component of the sodium-plus-potassium ion-activated adenosine triphosphatase

1974 ◽  
Vol 137 (2) ◽  
pp. 253-262 ◽  
Author(s):  
Denis R. Alexander ◽  
Richard Rodnight
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Ph Value ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gels ◽  
Ph Profile ◽  
Fast Running ◽  
Neutral Conditions ◽  
Strong Acids

1. Ox brain microsomal fractions were labelled with [32P]ATP in the presence of Na+ and the reaction was stopped with sodium dodecyl sulphate. The Na+-dependent bound phosphate was isolated on Sephadex G-25 and by acetone precipitation. The bound phosphate isolated under these neutral conditions was labile to hydroxylamine and gave the same pH profile of hydrolysis as that isolated by precipitation with strong acids. 2. When membrane protein was labelled with [32P]ATP, solubilized with sodium dodecyl sulphate and fractionated on Sepharose 6B, the Na+-dependent label emerged in a peak corresponding to protein of molecular weight 570000–580000. On fractionation of this protein peak on polyacrylamide gels containing detergent and urea, the Na+-dependent label occurred in a single band corresponding to a protein of molecular weight 102000. 3. Fractionation on Sepharose 6B of protein labelled with [32P]ATP in the absence of Na+ revealed three labelled peaks, one of which corresponded in position to the Na+-dependent label. Electrophoresis of this peak material on polyacrylamide gels showed that most of the label occurred in two fast-running bands. Cyclic AMP stimulated the labelling in these two bands, but had no effect on the labelling of the band corresponding in position to the Na+-dependent label. 4. Di-isopropyl [32P]phosphorofluoridate also labelled the band corresponding to the Na+-dependent label on gel electrophoresis. The labelling of this band by the reagent was inhibited by 50–60% by 3mm-ATP, but there was no evidence to suggest that the group labelled is normally phosphorylated by ATP.

scholarly journals A comparative study of the removal of lead, cadmium and zinc ions from aqueous solutions by natural and Fe(III)-modified zeolite

2014 ◽  
Vol 20 (2) ◽  
pp. 283-293 ◽  
Author(s):  
Marija Mihajlovic ◽  
Slavica Lazarevic ◽  
Ivona Jankovic-Castvan ◽  
Bojan Jokic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Natural Zeolite ◽  
Ph Value ◽  
Exchange Capacity ◽  
Ion Concentration ◽  
Point Of Zero Charge ◽  
Batch Adsorption ◽  
Modified Zeolite ◽  
Adsorption Mechanisms ◽  
Adsorption Capacities ◽  
Zero Charge

The main purpose of this research was to explain the differences in the adsorption mechanisms and adsorption capacities of natural and Fe(III)-modified zeolite for Pb2+, Zn2+ and Cd2+ ions. The adsorbents were characterized with respect to their phase composition, morphology, specific surface area, cation exchange capacity and point of zero charge. Batch adsorption experiments were performed as a function of the initial ion concentration and temperature, at constant initial pH value of 5.5 ? 0.1. The adsorption isotherms at 25, 40, 55 and 70?C suggest that the sequence of adsorption efficiency of both zeolites is Pb2+ > Zn2+ > Cd2+. The adsorption capacities of both zeolites increased with increasing temperature. The equilibrium adsorption data were best described by the Langmuir adsorption isotherm. This study revealed that the adsorption capacity of the Fe(III)-modified zeolite is much higher than that of natural zeolite for all investigated ions owing to the higher: specific adsorption caused by the new functional groups formed on the zeolite surface; ion exchange due to the presence of easily exchangeable ions; and hydroxide precipitation caused by higher point of zero charge of the Fe(III)-modified zeolite compared to natural zeolite.

Adsorption of Nickel and Cobalt Ions on Magnesium Silicate

2013 ◽  
Vol 726-731 ◽  
pp. 2855-2858
Author(s):  
Hua Yang ◽  
Hai Zeng Wang
Keyword(s):  
Ph Value ◽  
Average Pore Size ◽  
Chemical Properties ◽  
Magnesium Silicate ◽  
Solution Ph ◽  
Average Pore ◽  
Cobalt Ions ◽  
Physico Chemical ◽  
Short Time ◽  
Adsorption Desorption

Magnesium silicate (MS) was successfully prepared and the physico-chemical properties were determined by N2adsorption/desorption isotherm and Scanning Electron Microscopy (SEM). Surface area and the average pore size were 120 cm3·g-1and 10 nm. Adsorption experiments of removal of nickel and cobalt ions were investigated as the function of initial concentration, adsorbent dose, adsorption time and solution pH value. The maximum removal was reached with pH equal to 5 for the removal of nickel and cobalt ions. Adsorption process was rapid and adsorption equilibriums were attained in a short time.

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