scholarly journals 161 CALCINED CLAY AND ALUMINA AMENDMENTS INCREASE PO4 AND K RETENTION OF SOILLESS CONTAINER SUBSTRATES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 451g-452
Author(s):  
Kimberly A. Williams ◽  
Paul V. Nelson
Keyword(s):  
Aluminum Oxide ◽  
Adsorption Isotherms ◽  
Equilibrium Concentration ◽  
Calcined Clay ◽  
Substrate Solution ◽  
Greenhouse Study ◽  
P Concentration ◽  
Soil Solutions ◽  
Equilibrium P Concentration ◽  
Over Time

Soilless substrates have little capacity to sorb PO4. One way to reduce PO4 leaching during production is to increase the substrate retention of PO4. Adsorption isotherms were created at 25 C for alumina (aluminum oxide); the 2:1 calcined clays arcillite (montmorillonite plus illite) and attapulgite.; and a medium of 70 peat: 30 perlite using solutions of KH2PO4 at rates of P ranging from 0 to 20000 μg·ml-1. Material sorbed at the rate resulting in maximum P adsorption was then desorbed 22 times. Sorbing concentrations necessary to establish an equilibrium P concentration of 10 μg·ml-1 in the substrate solution were estimated from these curves. Materials were-charged with P at these estimated rates and evaluated in a greenhouse study in which each material was tested at 10 and 30% by volume of a 70 peat: 30 perlite substrate used to produce Dendranthema × grandiflorum `Sunny Mandalay'. Phosphate, K, and pH were determined on unaltered soil solutions biweekly throughout the cropping cycle and foliar analyses were determined on tissue collected at mid- and end-crop. Isotherm and greenhouse data indicated that alumina, arcillite, and attapulgite effectively retained and slowly released K as well as PO4 over time. Alumina was most effective at retaining P, sorbing 16800 μg/cc compared to 3100 and 7800 μg P sorbed/cc for arcillite and attapulgite, respectively, when sorbed at P concentrations resulting in an equilibrium concentration of approximately 10 μg P/ml.

scholarly journals Study of Adsorption from Dilute Aqueous Solutions on to Activated Carbon. Part 2. Some Exotic Adsorption Isotherms

1996 ◽  
Vol 13 (5) ◽  
pp. 341-354
Author(s):  
R. Mészáros ◽  
M. Nagy ◽  
G. Veress
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherms ◽  
Equilibrium Concentration ◽  
Model Description ◽  
Adsorption Data ◽  
Dilute Aqueous Solution ◽  
Dilute Aqueous Solutions ◽  
Error Terms ◽  
Concentration Curves ◽  
Supernatant Solution

Adsorption isotherms for the adsorption of 1-propanol and 2-propanol from dilute aqueous solution on to two types of activated carbon were presented at fixed different initial concentrations. The confidence limits for the specific excess relative to these fixed initial concentrations were also given. The high precision calculation of these error terms was based on the model description of the equilibrium concentration versus sorbent concentration curves discussed previously. The Dubinin–Radushkevich representation of the adsorption data was presented and tested for the same adsorption data. It appears that in some cases the adsorbed amount as expressed by the specific excess depends not only on the equilibrium concentration of the supernatant solution but also on the initial concentration and sorbent concentration. The so-called characteristic isotherms were also calculated in order to compare the various adsorption systems.

Influence of Air Abrasion and Long-term Storage on the Bond Strength of Self-etching Adhesives to Dentin

10.2341/06-61 ◽  
2007 ◽  
Vol 32 (3) ◽  
pp. 217-224 ◽  
Author(s):  
F. M. G. França ◽  
A. J. S. Santos ◽  
J. R. Lovadino
Keyword(s):  
Bond Strength ◽  
Aluminum Oxide ◽  
Clinical Relevance ◽  
Air Abrasion ◽  
Long Term Storage ◽  
Term Storage ◽  
Over Time

Clinical Relevance The adhesiveness of self-etching systems, used with aluminum oxide air abrasion to dentin, decreases over time.

Soil pH and Cation Exchange Capacity Affects Sunflower Tolerance to Sulfentrazone

2004 ◽  
Vol 18 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Gregory W. Kerr ◽  
Phillip W. Stahlman ◽  
J. Anita Dille
Keyword(s):  
Cation Exchange ◽  
Soil Ph ◽  
Cation Exchange Capacity ◽  
Dry Matter ◽  
Exchange Capacity ◽  
Treated Soil ◽  
Sunflower Plant ◽  
Greenhouse Study ◽  
Leaf Chlorosis ◽  
Over Time

Effects of soil pH and cation exchange capacity (CEC) on sunflower tolerance to sulfentrazone were investigated in a greenhouse study. Variables were soil pH (7.0, 7.3, 7.5, and 7.8), soil CEC (8.2, 13.7, 18.4, and 23.3 cmol/kg), and sulfentrazone rate (0, 105, 158, and 184 g ai/ha). Sulfentrazone-induced leaf chlorosis was affected by soil pH at 12 d after planting (DAP), but plants recovered, and earlier differences were not visible 9 d later. At 12 DAP, leaf chlorosis was 3 or 4% more severe in soils with pH 7.3 or higher compared with soils with pH 7.0 when averaged over both sulfentrazone rate and soil CEC. Leaf chlorosis resulting from sulfentrazone rates of 105, 158, and 184 g/ha was 17, 25, and 35% less at 23 cmol/kg than at 8.2 cmol/kg, respectively. Differences in chlorosis among sulfentrazone rates were greatest in soil with low CEC and lessened as soil CEC increased. Plants regained normal color over time, and newly emerging leaves were not affected. However, plant dry weights were reduced when sulfentrazone rate was ≥158 g/ha. Averaged over sulfentrazone rate and soil pH, sunflower dry weights were less when soil CEC was 8.2 compared with a CEC of 13.7 cmol/kg or higher, indicating a greater response at low CEC. Sunflower plant dry matter was not different in sulfentrazone-treated soil with a CEC above 13.7 cmol/kg. At the ranges tested, soil CEC had a considerably greater effect than did pH on sunflower tolerance to sulfentrazone.

scholarly journals Arsenic removal properties by electrolyzed and calcined manganese dioxide

2019 ◽  
Vol 25 (5) ◽  
pp. 735-741
Author(s):  
Yong-Jun Jung ◽  
Yuki Kamimoto
Keyword(s):  
Water Treatment ◽  
Adsorption Capacity ◽  
Adsorption Isotherms ◽  
Arsenic Removal ◽  
Equilibrium Concentration ◽  
Feed Solution ◽  
Ceramic Particle ◽  
Treatment Processes ◽  
Freundlich Equation ◽  
Arsenate Adsorption

As(V) removal properties of manganese dioxides which are commonly used for the removal of manganese in water treatment processes were evaluated in this paper. The following manganese dioxides were used: two types of powdered manganese dioxides powdered or electrolyzed MnO<sub>2</sub> (g-structure) and calcined MnO<sub>2</sub> (b-structure), and a granular MnO<sub>2</sub>, which was prepared by coating MnO<sub>2</sub> onto a ceramic particle. The maximum arsenate adsorption capacity of the electrolyzed and calcined MnO<sub>2</sub> was 2.22 and 2.26 mg-As g<sup>-1</sup>, respectively. The adsorption capacity of the granular MnO<sub>2</sub> was 0.543 mg-As g<sup>-1</sup> and this value corresponded to the MnO<sub>2</sub> content (23.2%) of the granular adsorbent. When an arsenate solution of 0.1 mg-As L<sup>-1</sup> was fed into the column (10 mm i.d.; 100 mm long) packed with the granular MnO<sub>2</sub> at SV = 20 h<sup>-1</sup>, the column received 28.9 L of the feed solution (3,580 times the bed volume) before the breakthrough point (0.01 mg-As L<sup>-1</sup>). The adsorption isotherms for the electrolyzed and granular MnO<sub>2</sub> were approximated by the modified Langmuir equations. On the other hand, the adsorption isotherm for the calcined MnO<sub>2</sub> was approximated by the Freundlich equation. Based on the adsorption isotherms, the As(V) adsorption amounts at 0.01 mg-As L<sup>-1</sup> of the equilibrium concentration were evaluated as follows: 1.27 mg-As g<sup>-1</sup> for the electrolyzed MnO<sub>2</sub>, 1.20 mg-As g<sup>-1</sup> for the calcined one, and 0.29 mg-As g<sup>-1</sup> for the granular one. Since granular MnO<sub>2</sub> has been commonly used for the removal of manganese from water treatment systems, the process can be also applied to arsenate removal.

scholarly journals Root Respiration and Phosphorus Nutrition of Tomato Plants Grown at a 36 °C Root-zone Temperature

1997 ◽  
Vol 122 (2) ◽  
pp. 175-178 ◽  
Author(s):  
Kimberly A. Klock ◽  
Henry G. Taber ◽  
William R. Graves
Keyword(s):  
Phosphatase Activity ◽  
Root Respiration ◽  
Root Zone ◽  
Root Surface ◽  
P Uptake ◽  
Root Zone Temperature ◽  
Tomato Plants ◽  
P Acquisition ◽  
P Concentration ◽  
Over Time

Growth of tomato (Lycopersicon esculentum Mill.) plants decreases at root-zone temperatures (RZTs) >30 °C, but no research has been conducted on the effects of changes in root respiration on P acquisition at supraoptimal RZT. We monitored the changes every 3 to 5 days in root respiration, root surface phosphatase activity, and P acquisition of `Jet Star' tomato plants grown in Hoagland's no. 1 solution held at 25 and 36 °C RZT for 19 days. Root respiration rate in plants grown at 25 °C increased linearly from RZT initiation to day 12, but there was no difference in respiration between days 12 and 19. Root respiration at 36 °C, however, increased from RZT initiation to day 8 and then decreased. Shoot P concentration and root phosphatase activity for plants grown at 25 °C did not change during the experiment. Shoot P concentration for plants at 36 °C, however, linearly decreased over time, and root phosphatase activity linearly increased over time. Decreased shoot growth and demand for P along with decreased root respiration after day 8 probably resulted in the decreased P uptake and shoot P concentration in plants grown at 36 °C RZT.

Phosphate and arsenate retention in sediments of the Anllóns river (northwest Spain)

2003 ◽  
Vol 48 (10) ◽  
pp. 159-166 ◽  
Author(s):  
D. Rubinos ◽  
M.T. Barral ◽  
B. Ruiz ◽  
M. Ruiz ◽  
M.E. Rial ◽  
...  
Keyword(s):  
Gold Mining ◽  
River Sediments ◽  
Sorption Isotherms ◽  
Mining Activity ◽  
Arsenic Content ◽  
Sorption Behavior ◽  
Nw Spain ◽  
The Past ◽  
P Concentration ◽  
Equilibrium P Concentration

We have studied the distribution and sorption behavior of phosphate and arsenate in bed-sediments of the Anllóns river (NW Spain). As a consequence of the intense gold-mining activity in the past, substantial amounts of arsenic were found in the river sediments. For phosphorus, higher concentrations were found near two sources of P pollution. Sorption isotherms were described by the Freundlich, Langmuir and Tempkin equations. In general, the sediments sorbed more P than As. The equilibrium P concentration (EPC) reveals that sediments act as a scavenger for soluble P; by contrast, equilibrium As concentration (EAC) values were high for the As-rich sediments and correlates well with total arsenic content. Amorphous Fe oxides content, organic matter and fraction of clay plus silt were the main properties of the sediments related with the sorption of arsenate and phosphate. The results obtained provide a first estimate of the sorption behavior and availability of the phosphate and arsenate anions in the sediments of the Anllóns river.

scholarly journals Adsorptive Removal of Copper by Using Surfactant Modified Laterite Soil

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Tien Duc Pham ◽  
Hoang Hiep Nguyen ◽  
Ngoc Viet Nguyen ◽  
Thanh Tu Vu ◽  
Thi Ngoc Mai Pham ◽  
...  
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherms ◽  
Salt Concentration ◽  
Copper Ions ◽  
Sodium Dodecyl ◽  
Equilibrium Concentration ◽  
Total Carbon ◽  
Adsorption Model ◽  
Flame Atomic Absorption ◽  
Ft Ir

Removal of copper ion (Cu2+) by using surfactant modified laterite (SML) was investigated in the present study. Characterizations of laterite were examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma mass spectrometry (ICP-MS), and total carbon analysis. The optimum conditions for removal of Cu2+ by adsorption using SML were systematically studied and found as pH 6, contact time 90 min, adsorbent dosage 5 mg/mL, and ionic strength 10 mM NaCl. The equilibrium concentration of copper ions was measured by flame atomic absorption spectrometry (F-AAS). Surface modification of laterite by anionic surfactant sodium dodecyl sulfate (SDS) induced a significant increase of the removal efficiency of Cu2+. The surface modifications of laterite by preadsorption of SDS and sequential adsorption of Cu2+ were also evaluated by XRD and FT-IR. The adsorption of Cu2+ onto SML increases with increasing NaCl concentration from 1 to 10 mM, but at high salt concentration this trend is reversed because desorption of SDS from laterite surface was enhanced by increasing salt concentration. Experimental results of Cu2+/SML adsorption isotherms at different ionic strengths can be represented well by a two-step adsorption model. Based on adsorption isotherms, surface charge effects, and surface modification, we suggest that the adsorption mechanism of Cu2+ onto SML was induced by electrostatic attraction between Cu2+ and the negatively charged SML surface and nonelectrostatic interactions between Cu2+ and organic substances in the laterite.

scholarly journals Aluminum Amendments Increase Retention of Triple Superphosphate-P in Soilless Container Media

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 763D-763
Author(s):  
Kimberly A. Williams ◽  
Paul V. Nelson
Keyword(s):  
Plant Growth ◽  
Adsorption Isotherms ◽  
Low Ph ◽  
Triple Superphosphate ◽  
Dendranthema Grandiflorum ◽  
Greenhouse Study ◽  
Medium Components ◽  
P Retention

Soilless container medium components such as peatmoss and perlite have almost no capacity to retain PO4-P, and preplant amendments of triple superphosphate (TSP) are readily leached. Al amendments were tested to reduce P losses from these media. Al2(SO4)3 solutions at rates of 320 and 960 μg Al/cc were applied to a 70 peat: 30 perlite medium and dried at 70C. Adsorption isotherms were created at 25C for the Al2(SO4)3-amended media and an unamended control using solutions of Ca(H2PO4)2 at concentrations of P ranging from 0 to 500 μg·ml–1. Isotherms showed that P retention increased as Al concentration increased. In a greenhouse study, Dendranthema ×grandiflorum `Sunny Mandalay' was grown in these media with 100 g P/m3 from TSP incorporated into the mixes before planting. PO4-P, soluble Al, and pH were determined on unaltered medium solutions collected throughout the cropping cycle and foliar analyses were determined on tissue collected at mid- and end-crop. The highest rate of Al was excessive and resulted in low pH and soluble Al levels in the medium solution early and in the cropping cycle, which were detrimental to plant growth. When Al was applied at 320 μg/cc, soluble Al levels in medium solution were not significantly higher than in the unamended control, PO4-P leached from TSP was reduced, and sufficient PO4-P was released throughout the cropping cycle to result in optimal plant growth.

scholarly journals Time-series responses of swine plasma metabolites to ingestion of diets containingmyo-inositol or phytase

2017 ◽  
Vol 118 (11) ◽  
pp. 897-905 ◽  
Author(s):  
Aaron J. Cowieson ◽  
Franz F. Roos ◽  
Jean-Paul Ruckebusch ◽  
Jonathan W. Wilson ◽  
Patrick Guggenbuhl ◽  
...  
Keyword(s):  
Time Series ◽  
Oral Delivery ◽  
Dietary Treatment ◽  
Basal Diet ◽  
Automated System ◽  
Plasma Metabolites ◽  
Post Feeding ◽  
P Concentration ◽  
Over Time ◽  
Rapid Appearance

AbstractThe effect of the ingestion of diets containing eithermyo-inositol or exogenous phytase on plasma metabolites was examined using 29 kg barrows. The diets were: control (maize, soya, rapeseed, rice bran), control plus 2 g/kgmyo-inositol, control plus 1000 phytase units (FYT)/kg or 3000 FYT/kg exogenous phytase. Pigs were housed in a PigTurn device and blood was collected, from jugular catheters, via an automated system at −30, (30 min before feeding), 0, 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 and 360 min post-feeding. The addition of 2 g/kgmyo-inositol to the basal diet resulted in an increase in plasmamyo-inositol concentration that was evident 45–60 min after diet introduction and persisted to 360 min post-feeding. Similarly, supplementation of the basal diet with either 1000 or 3000 FYT/kg exogenous phytase resulted in an increase in plasmamyo-inositol concentration that was still rising 360 min post-feeding. Plasma P concentration was increased over time by the addition of 1000 and 3000 FYT/kg phytase, but not by the addition ofmyo-inositol. Other plasma metabolites examined were not affected by dietary treatment. It can be concluded that oral delivery ofmyo-inositol results in rapid increase in plasmamyo-inositol concentrations that peak approximately 45–60 min after feeding. Use of supplemental phytase achieves similar increases inmyo-inositol concentration in plasma but the appearance is more gradual. Furthermore, supplementation of pig diets with exogenous phytase results in rapid appearance of P in plasma that may be sustained over time relative to diets with no added phytase.

scholarly journals A Study of Using Natural Sorbent to Reduce Iron Cations from Aqueous Solutions

2020 ◽  
Vol 17 (10) ◽  
pp. 3686 ◽  
Author(s):  
Iveta Pandová ◽  
Miroslav Rimár ◽  
Anton Panda ◽  
Jan Valíček ◽  
Milena Kušnerová ◽  
...  
Keyword(s):  
Adsorption Isotherms ◽  
Natural Zeolite ◽  
Aqueous Media ◽  
Steel Production ◽  
Equilibrium Concentration ◽  
Optimal Time ◽  
Kinetic Properties ◽  
Natural Sorbent ◽  
Wastewater Treatment Process ◽  
Ferric Cation

Iron is an essential trace element, but at high doses, this element may pose a health risk. Wastewater from iron ore mining, steel production, and metal processing, among other heavy metals, also contains high concentrations of iron (Fe3+). The use of sorption on natural materials is a potential alternative to conventional methods for removing iron ions, also because of low cost. The methods presented in this article are based on the study of kinetic properties and the acquisition of adsorption isotherms, which are one of the most important characteristics of adsorption mechanisms. The course of sorption is analyzed according to the Freundlich sorption isotherm model. Isotherm parameters are evaluated using experimental results of ferric cation sorption. The results presented relate to the investigation of natural zeolite-clinoptilolite as a ferric cation sorbent, providing a measurement of the sorption kinetics as well as the observed sorption parameters of iron cations from aqueous media. The optimal time for equilibrium in the adsorption system is determined from the kinetic dependencies. The dependence of the achieved equilibrium concentration on the initial concentration of the solution was also expressed, both graphically and analytically. The new prediction model was compared with the traditional Freundlich model. Finally, adsorption isotherms tested under laboratory conditions for a practical application can be recommended for the preliminary examination of the possible technological use of natural zeolite in the wastewater treatment process.

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