Adsorption of Some Metal Ions on the Surface of Calcium Sulphate Dihydrate Crystals in Artificial Sea Water

1995 ◽  
Vol 8 (1) ◽  
pp. 41-48
Author(s):  
S. HAMDONA ◽  
W. ABOULNAGA
Keyword(s):  
Metal Ions ◽  
Sea Water ◽  
Calcium Sulphate

scholarly journals Spring and surface water quality of the Cyprus ophiolites

2002 ◽  
Vol 6 (5) ◽  
pp. 797-817 ◽  
Author(s):  
C. Neal ◽  
P. Shand
Keyword(s):  
Water Quality ◽  
Sea Water ◽  
Stream Water ◽  
Chemical Reactivity ◽  
Surface Water Quality ◽  
Calcium Sulphate ◽  
Stream Water Quality ◽  
Troodos Ophiolite ◽  
High Calcium ◽  
Hydrolysis Of

Abstract. A survey of surface, spring and borehole waters associated with the ophiolite rocks of Cyprus shows five broad water types (1) Mg-HCO3, (2) Na-SO4-Cl-HCO3, (3) Na-Ca-Cl-SO4-OH-CO3, (4) Na-Cl-SO4 and (5) Ca-SO4. The waters represent a progression in chemical reactivity from surface waters that evolve within a groundwater setting due to hydrolysis of the basic/ultrabasic rock as modified by CO2-weathering. An increase in salinity is also observed which is due to mixing with a saline end-member (modified sea-water) and dissolution of gypsum/anhydrite. In some cases, the waters have pH values greater than 11. Such high values are associated with low temperature serpentinisation reactions. The system is a net sink for CO2. This feature is related not only to the hydrolysis of the primary minerals in the rock, but also to CaCO3 or Ca-Mg-CO3 solubility controls. Under hyperalkaline conditions, virtually all the carbon dioxide is lost from the water due to the sufficiently high calcium levels and carbonate buffering is then insignificant. Calcium sulphate solubility controls may also be operative when calcium and sulphate concentrations are particularly high. Keywords: Cyprus, Troodos, ophiolite, serpentinisation, spring, stream, water quality, bromide, iodine, boron, trace elements, hyperalkaline.

Eco-design of nanostructured cellulose sponges for sea-water decontamination from heavy metal ions

2020 ◽  
Vol 246 ◽  
pp. 119009 ◽  
Author(s):  
Andrea Fiorati ◽  
Giacomo Grassi ◽  
Aurora Graziano ◽  
Giulia Liberatori ◽  
Nadia Pastori ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Sea Water ◽  
Water Decontamination

scholarly journals Effect of Nobel Metal Ions on the Synthesis of Metal Nanoclusters for Selective Detection of Various Heavy Metals

2020 ◽  
Author(s):  
AMIT NAIN
Keyword(s):  
Metal Ions ◽  
Photoelectron Spectroscopy ◽  
Sea Water ◽  
Metal Nanoclusters ◽  
Average Life ◽  
Metal Core ◽  
X Ray ◽  
Metal Metal ◽  
Pl Quenching

In this study, effect of noble metal ions (Au, Ag and Cu) on the synthesis of metal nanoclusters (MNCs) have been investigated. Through heating at 70ºC, TSA/BSA–Au, –Ag and –Cu NCs were separately prepared from Au3+, Ag+ and Cu2+ respectively in the presence of bovine serum albumin (BSA) and thiosalicylic acid (TSA). They exhibit photoluminescence (PL) at 700, 624 and 430 nm, with an average life times of 1500, 100 and 11.71 ns, respectively, when excited at 350 nm. X–ray photoelectron spectroscopy (XPS) data support the presence of metal core (M0) and metal–thiolate shell (Mn–SRm) in each of the TSA/BSA–Metal nanoclusters (MNCs). Spectroscopic measurements reveal the formation of Au32–SR, Ag9–SR and (Cu4–Cu13)–SR species in the TSA/BSA–Au, –Ag and –Cu NCs respectively. Through PL quenching of the TSA/BSA–Au, –Ag and –Cu NCs, they have been used separately for quantitation of Hg2+, As3+ and Cr6+ , with linear ranges of 1400, 418, and 40400 nM and limits of detection (LODs) of 0.25, 2.34 and 3.54 nM, respectively. The PL quenching is mainly due to aggregation of the MNCs via metal–metal or metal–thiol interaction. The stable TSA/BSA–Au, –Ag and –Cu NCs have been employed separately for the determination of the concentrations of Hg2+, As3+ and Cr6+ ions in the spiked sea water samples, showing advantages of simplicity, rapidity, high selectivity, and sensitivity.

scholarly journals Transformation Kinetics of Burnt Lime in Freshwater and Sea Water

2020 ◽  
Author(s):  
Harald Justnes ◽  
Carlos Escudero-Oñate ◽  
Øyvind Aaberg Garmo ◽  
Martin Mengede
Keyword(s):  
Calcium Hydroxide ◽  
Magnesium Hydroxide ◽  
Open System ◽  
Sea Water ◽  
Particle Surface ◽  
Calcium Sulphate ◽  
Burnt Lime ◽  
Common Ion ◽  
The Common ◽  
Kinetics Of

The reaction kinetics of burnt lime (CaO) in contact with sea water has been elucidated and compared to its behaviour in fresh water. In the first minutes of contact between burnt lime and water, it "slaked" as CaO reacted with water to yield calcium hydroxide (Ca(OH)2). Subsequently, calcium hydroxide reacted with magnesium, sulphate and carbonate from the sea water to yield magnesium hydroxide (Mg(OH)2), calcium sulphate dihydrate (gypsum, CaSO4·2H2O) and calcium carbonate (CaCO3), respectively. In a closed system of 1% CaO in natural sea water (where the supply of sulphate, magnesium and carbonate is limited), more than 90% reacted within the first 5 hours. It is foreseen that in an open system, like a marine fjord, it will react even faster. The pH 8 of sea water close to the CaO particle surface will immediately increase to a theoretical value of about 12.5 but will, in an open system with large excess of sea water, rapidly fall back to pH 10.5 being equilibrium pH of magnesium hydroxide. This is further reduced to < 9 due to the common ion effect of dissolved magnesium in sea water and then be diluted to the sea water background pH, about 8. Field test dosing CaO particles to sea water showed that the pH of water between the particles stayed around 8.

Calcium sulphate scale deposition in sea water evaporators

Desalination ◽  
1967 ◽  
Vol 2 (3) ◽  
pp. 308-324 ◽  
Author(s):  
H.C. Simpson ◽  
M. Hutchinson
Keyword(s):  
Sea Water ◽  
Calcium Sulphate ◽  
Scale Deposition

Study of the features of sorption of metal ions from sea water on clinoptilolite from different deposits

1988 ◽  
Vol 37 (11) ◽  
pp. 2215-2219
Author(s):  
R. Kh. Khamizov ◽  
T. Yu. Butenko ◽  
L. V. Bronov ◽  
V. V. Skovyra ◽  
V. A. Novikova
Keyword(s):  
Metal Ions ◽  
Sea Water
Sign in / Sign up

Export Citation Format

Share Document