Investigation of Cu(II) adsorption from aqueous solutions by NKF-6 zeolite

2011 ◽  
Vol 63 (3) ◽  
pp. 395-402 ◽  
Author(s):  
H. Zhang ◽  
D. Zhao ◽  
L. Chen ◽  
X. J. Yu
Keyword(s):  
Aqueous Solutions ◽  
Outer Sphere ◽  
Low Ph ◽  
Ambient Conditions ◽  
Temperature Dependent ◽  
Ph Values ◽  
Batch Technique ◽  
Negative Effect ◽  
High Level ◽  
Positive Effect

Adsorption of Cu(II) from aqueous solutions using NKF-6 zeolite was investigated by batch technique under ambient conditions. The adsorption was investigated as a function of pH, ionic strength, fulvic acid (FA), foreign ions and temperature. The results indicated that the adsorption of Cu(II) on NKF-6 zeolite gradually increases from 0 to 90% with increasing pH at pH<6.5, and maintains high level at pH>6.5. Outer-sphere complexation or ion exchange may be the main adsorption mechanism of Cu(II) to NKF-6 zeolite at low pH values, whereas the adsorption of Cu(II) at pH>6.5 is mainly dominated by inner-sphere complexation or precipitation. A positive effect of FA on Cu(II) adsorption onto NKF-6 zeolite is observed at low pH values, while a negative effect of FA is observed at high pH values. The thermodynamic parameters (i.e., ΔH0, ΔS0 and ΔG0) for the adsorption of Cu(II) were determined from the temperature dependent isotherms at 20, 40 and 60°C, respectively, and the results indicated that the adsorption reaction is favoured at low temperature. The results suggested that the adsorption process of Cu(II) on NKF-6 zeolite is spontaneous and exothermic.

scholarly journals KORUPSI DAN PERTUMBUHAN EKONOMI

2020 ◽  
Vol 5 (2) ◽  
pp. 154-165
Author(s):  
Amin Haqiqi ◽  
◽  
Husaeri Putra ◽  
Keyword(s):  
Economic Growth ◽  
Cultural Differences ◽  
Economic Freedom ◽  
Scientific Research ◽  
Research Articles ◽  
Literature Study ◽  
Negative Effect ◽  
Scientific Research Articles ◽  
High Level ◽  
Positive Effect

This study analyzes corruption and economic growth. The method of analysis uses literature studies. This literature study was carried out by searching scientific research articles about corruption through Google Scholar and journals about corruption. After the identification of several articles, the results show different results about the effect of corruption on economic growth. From each journal shows Corruption has a negative effect on economic growth in Indonesia and those that have a positive effect. This shows several factors that underlie the influence of corruption on economic growth, namely due to cultural differences, policies, economic freedom and the rules of each region. The diversity of each region in Indonesia makes a different level of influence of corruption so that if a region has a high level of economic freedom and rules and bureaucracy that are not difficult, corruption has a positive effect on economic growth. In general, the effect of corruption on economic growth is negative, where the cleaner the region or region is from corruption, the more it will encourage the growth of the region.

scholarly journals Adsorption Properties of Sepiolite in Relation to Uranium and Lanthanide Ions

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 686 ◽  
Author(s):  
Gładysz-Płaska
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Properties ◽  
Lanthanide Ions ◽  
Ambient Conditions ◽  
Initial Concentration ◽  
Ph Values ◽  
Batch Technique ◽  
Effects Of Ph ◽  
Ph Range

The batch technique was used to study the adsorption of La(III), Eu(III), Lu(III), and U(VI) ions on sepiolite and ODTMA–sepiolite under ambient conditions. The effects of pH, time, and initial concentration were investigated. The highest U(VI) adsorption was found on ODTMA-sepiolite in the pH range of 6–8, while in the case of lanthanide ions, adsorption on sepiolite was 80% in the pH range of 4–8 and 98% for pH values above 8. The adsorption capacity of ODTMAsepiolite was found to be 285.6 mg/g for uranium, and raw sepiolite: 142.8 mg/g for U(VI), 91.6 mg/g for La(III), 91.4 mg/g for Eu (III), and 104.9 mol/g for Lu(III). ODTMA–sepiolite turned out to be a weak sorbent for lanthanide ions. Two short- and long-lived fluorescence species were observed in the TRLFS spectra of U(VI) adsorbed on sepiolite at pH 6.5. The average lifetimes of short- (τ1) and long-lived (τ2) fluorescence are τ1 = 2420 ± 430 ns and τ2 = 37950 ± 5710 ns for U-sepiolite; τ1 = 3523 ± 160 ns and τ2 = 45400 ± 1830 ns for U-ODTMA–sepiolite.

scholarly journals Boron removal from aqueous solutions by a polyethylenimine-epichlorohydrin resin

2018 ◽  
Vol 83 (2) ◽  
pp. 251-264 ◽  
Author(s):  
Sofia Sarri ◽  
Panagiotis Misaelides ◽  
Dimitrios Zamboulis ◽  
Jolanta Warchoł
Keyword(s):  
Aqueous Solutions ◽  
Boron Concentration ◽  
Kinetic Studies ◽  
Alkaline Solutions ◽  
Competitive Sorption ◽  
Boron Removal ◽  
Boron Uptake ◽  
Acidic Solutions ◽  
Ph Values ◽  
Batch Technique

The use of a polyethylenimine?epichlorohydrin resin for the boron removal from aqueous solutions (boron concentration: 100?5000 mg L-1) of non-adjusted and pre-adjusted pH (pHnat, pHinit 8.0, 9.0 and 10.0) aqueous solutions was investigated using a batch technique. The boron concentration in the solutions after sorption was determined photometrically. The results indicated that the pH-dependent boron uptake was related to the protonation/deprotonation of the surface functional groups of the resin and to the boron speciation in solutions of different pH values. The maximum boron sorption capacity observed in solutions of pH 9.0 was 55 mg g-1 exceeding the majority of other commercial or alternative sorbents. Five empirical adsorption equations (Freundlich, Langmuir, Redlich?Peterson, Langmuir?Freundlich and Toth) were applied to the modelling of the boron adsorption equilibrium. The modelling results identified the homogenous boron sorption from acidic and heterogeneous from alkaline solutions. At alkaline pH, the system non-ideality can originate either from the different binding mechanism or from the competitive sorption of different boron species. The homogenous type boron sorption from acidic solutions was further confirmed by kinetic studies

Influence of soil humic acid and fulvic acid on sorption of thorium(IV) on MX-80 bentonite

2006 ◽  
Vol 94 (8) ◽  
Author(s):  
D. Xu ◽  
X. K. Wang ◽  
C. L. Chen ◽  
X. Zhou ◽  
X. L. Tan
Keyword(s):  
Humic Acid ◽  
Fulvic Acid ◽  
Sorption Isotherms ◽  
Positive Influence ◽  
Low Ph ◽  
Ph Values ◽  
Batch Technique ◽  
Soil Humic Acid ◽  
Drastic Effect ◽  
Chemical Analogue

SummaryTh(IV) is considered herein as a chemical analogue of other actinides (IV). Effect of pH, ionic strength and humic acid/fulvic acid concentrations on the sorption of thorium(IV) to MX-80 bentonite was studied by batch technique. The sorption isotherms were acquired by varying pH in the range of 0.5–12 and FA/HA concentration in the range of 2–20 mg/L. The results indicate that soil fulvic acid has higher carboxylic content than humic acid, and has stronger positive influence on the sorption of Th(IV) on bentonite at low pH values than humic acid. The increase of FA/HA concentration results in a slight increase of Th(IV) sorption on FA/HA coated bentonite. The results of no drastic effect of different addition sequences of FA/HA and Th(IV) to bentonite suspension on Th(IV) sorption in the ternary system HA/FA-Th(IV)-bentonite indicate that both the Th(IV)-HA/FA complexation and HA/FA-bentonite sorption do not affect the sorption of Th(IV) on HA/FA coated bentonite obviously. The samples were also measured by SEM method and the results show that the surface properties of different samples are different.

Removal of thorium(IV) from aqueous solutions by natural sepiolite

2017 ◽  
Vol 105 (3) ◽  
Author(s):  
Kadriye Esen Erden ◽  
Ramazan Donat
Keyword(s):  
Aqueous Solutions ◽  
Thermodynamic Data ◽  
Adsorption Process ◽  
Adsorption Efficiency ◽  
Optimum Conditions ◽  
High Adsorption ◽  
Ph Values ◽  
Batch Technique

AbstractNatural sepiolite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions by batch technique. Effects of various parameters on the adsorption process have been investigated. Under optimum conditions, Th(IV) was adsorbed with high adsorption efficiency. The results indicated that sorption of Th(IV) on sepiolite was strongly affected by pH values and temperature. The adsorption patterns of thorium on the sepiolite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The thermodynamic data (Δ

Photocatalytic decolourization of the X3B textile dye in aqueous solutions using iron-rich montmorilloniteA paper submitted to the Journal of Environmental Engineering and Science.

2009 ◽  
Vol 36 (7) ◽  
pp. 1265-1271
Author(s):  
Zong-ping Wang ◽  
Li-zhi Huang ◽  
Lin Du ◽  
Hua Sheng ◽  
Bo Lv
Keyword(s):  
Aqueous Solutions ◽  
Butyl Alcohol ◽  
Low Ph ◽  
Textile Dye ◽  
Dye Wastewater ◽  
Ph Values ◽  
Tert Butyl Alcohol ◽  
Nano Clay ◽  
Uv Lamp ◽  
Structural Iron

Photocatalytic decolourization of textile dye X3B in aqueous solutions was investigated, using iron-rich montmorillonite (MMt, 2.24%Fe2O3) under a 15 W low-pressure UV lamp (λ = 254 nm, I = 48.4 μW/cm2). Hydroxyl radicals (•OH) were detected by tert-butyl alcohol (TBA) in aqueous MMt suspensions under UV irradiation and were found to be responsible for the degradation of X3B. Free iron ions dissolved in MMt suspensions, structural iron in the MMt solid, and the charged surface of nano clay are responsible for hydroxyl radical (•OH) production. Low pH values are favorable for the decolourization of X3B. The •OH concentration increased with increasing aqueous MMt concentrations in the range of 0 – 2.0 g/L; higher concentrations, for example, 5.0 g/L MMt, inhibited the •OH production. The addition of oxalate was favorable for X3B photodegradation in acid-washed MMt suspensions. This study shows that iron-rich MMt is a potential photocatalyst for the treatment of dye wastewater.

scholarly journals Physiological and cytological aspects of Inga vera subsp. affinis embryos during storage

2006 ◽  
Vol 18 (4) ◽  
pp. 503-513 ◽  
Author(s):  
José M.R. Faria ◽  
Lisete C. Davide ◽  
Edvaldo A. A. da Silva ◽  
Antonio C. Davide ◽  
Roselaine C. Pereira ◽  
...  
Keyword(s):  
Ex Situ Conservation ◽  
Ex Situ ◽  
Rapid Decline ◽  
Starch Granules ◽  
Embryo Viability ◽  
Temperature Dependent ◽  
Negative Effect ◽  
Positive Effect ◽  
Cellular Alterations ◽  
Dependent Interaction

The remarkably short storability of recalcitrant seeds has prevented their inclusion in programs of ex situ conservation. The causes of their desiccation sensitivity and rapid decline in viability during storage are not fully elucidated yet. In this study the highly recalcitrant, fully viable embryos of the tree species Inga vera subsp. affinis were stored under various conditions and analyzed physiologically and cytologically at intervals, in order to obtain more insights in their loss of viability during storage. Embryos stored fully hydrated at 5ºC fully lost viability in 18 d. Sealed storage of partially dehydrated embryos slightly prolonged their viability, with 95% germination being attained after 14 d of storage. However, after 30 d of storage, viability was completely lost. Storage of hydrated embryos in a solution of polyethylene glycol (PEG) at -1.7 MPa water potential was capable of maintaining high germinability until 30 d of storage. When added to the PEG solution, abscisic acid showed a strong temperature-dependent interaction, with a positive effect on the longevity of embryos stored at 20ºC and a negative effect on embryos stored at 5ºC. In any case, embryo viability could be maintained no longer than 50 d. Embryos from seeds collected from the same trees in the following year showed better storability and still attained 45% germination after 62 d of storage. Analysis of cellular alterations during storage and viability loss of the embryos showed disappearance of starch granules and various damages to the cells, such as cell wall folding and cytoplasm fragmentation.

INVESTIGATION OF SOME SOILS DEVELOPED IN HUMMOCKS OF THE CANADIAN SUB-ARCTIC AND SOUTHERN-ARCTIC REGIONS. 2. ANALYTICAL CHARACTERISTICS, GENESIS AND CLASSIFICATION

1975 ◽  
Vol 55 (3) ◽  
pp. 321-330 ◽  
Author(s):  
S. PAWLUK ◽  
R. BREWER
Keyword(s):  
Organic Matter ◽  
Arctic Region ◽  
Low Ph ◽  
Base Saturation ◽  
Freeze Thaw ◽  
Forest Tundra ◽  
Ph Values ◽  
Arctic Regions ◽  
High Level

Soils formed in mineral hummocks of the Forest–Tundra region have analytical characteristics reflecting "podzolic" processes. These soils have upper sola that are moderately to strongly acidic, with low pH values and base saturation; have high contents of organically complexed iron and aluminum; and show "chloritization" of montmorillonite, potassium removal from mica and moderate weathering of feldspars. Soils from the Southern-Arctic region have similar acidic characteristics but lack evidence for chemical and mineralogical weathering. Podzolic processes appear much weaker than in the Forest–Tundra region. However, soils from both regions are similar in morphological and micromorphological characteristics. A moderately high level of organic matter is present in the upper sola and at the permafrost interface. The soils are characterized by structures more closely reflecting freeze–thaw processes and faunal activity than podzolic alteration.

scholarly journals Pengaruh Nilai Pasar, Profitabilitas, dan Leverage terhadap Harga Saham (Studi pada Perusahaan Sektor Industri Barang Konsumsi yang Terdaftar di Bursa Efek Indonesia (BEI) Periode 2013—2017)

2019 ◽  
Vol 2 (2) ◽  
pp. 84-103
Author(s):  
Silviana Agustami ◽  
Pitriani Syahida
Keyword(s):  
Stock Price ◽  
Sampling Method ◽  
Stock Exchange ◽  
Market Value ◽  
Hypotheses Testing ◽  
Industry Sector ◽  
Negative Effect ◽  
High Level ◽  
Positive Effect

This study aims to determine the influence of market value, profitability, and leverage on the stock price of Consumer Goods Industry Sector Companies listed on the Indonesia Stock Exchange for the period 2013 to 2017. The sample of this study was 20 companies by using purposive sampling method. Hypotheses testing was done by using multiple regression analysis with software tools SPSS 24. The results of hypotheses testing showed that market value had a positive effect on stock price, profitability had a positive effect on stock price, and leverage had a negative effect on the stock price. So, the implications for the company are expected to be able to maintain the value of leverage. That is due to the use of large long-term debt that causes the company to have a high level of risk so that investors avoid investing in the company.

Working Memory, Mental Prospection, Time Orientation, and Cognitive Insight

2013 ◽  
Vol 34 (3) ◽  
pp. 159-169 ◽  
Author(s):  
Sevtap Cinan ◽  
Aslı Doğan
Keyword(s):  
Working Memory ◽  
Structural Equation ◽  
Factor Model ◽  
Time Orientation ◽  
Equation Modeling ◽  
Cognitive Insight ◽  
Confirmatory Factor ◽  
Negative Effect ◽  
Positive Effect ◽  
Three Factor

This research is new in its attempt to take future time orientation, morningness orientation, and prospective memory as measures of mental prospection, and to examine a three-factor model that assumes working memory, mental prospection, and cognitive insight are independent but related higher-order cognitive constructs by using confirmatory factor analysis (CFA). The three-factor model produced a good fit to the data. An alternative one-factor model was tested and rejected. The results suggest that working memory and cognitive insight are distinguishable, related constructs, and that both are distinct from, but negatively associated with, mental prospection. In addition, structural equation modeling (SEM) showed that working memory had a strong positive effect on cognitive insight and a moderate negative effect on mental prospection.

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