Heavy metals removal from wastewaters of phosphoric acid production: a comparison of hybrid liquid membrane (HLM) and aqueous hybrid liquid membrane (AHLM) technologies

2001 ◽  
Vol 1 (5-6) ◽  
pp. 119-129 ◽  
Author(s):  
V. Kislik ◽  
A. Eyal
Keyword(s):  
Heavy Metals ◽  
Phosphoric Acid ◽  
Cation Exchange ◽  
Liquid Membrane ◽  
Membrane Resistance ◽  
Water Soluble ◽  
Separation System ◽  
Membrane Systems ◽  
Membrane Pore ◽  
Cyanex 302

Selective removal of heavy metal ions from industrial wet-process phosphoric acid (WPA) was studied, using the two liquid membrane systems: Hybrid Liquid Membrane (HLM) and Aqueous Hybrid Liquid Membrane (AHLM). Monothiophosphinic acid (Cyanex 302) in kerosene (for the HLM) and Polyvinylsulfonic acid (PVSA) aqueous solution (for the AHLM) were used as a liquid membrane (LM), separated from the feed and strip streams by neutral or cation-exchange membranes. On application of the HLM separation system, the permeation from the feed to the strip phase followed the selectivity sequence: Zn >> Cd > Cu with all types of membranes used. Results show that the selective separation of Cd and Zn from the WPA may be achieved by the HLM with cation-exchange membranes, using a single set-up installation at continuous processing. Copper is accumulated in the Cyanex 302, poisoning the carrier. So, this carrier and HCl as a strip solution can not be recommended for the HLM processing of WPA. Using the AHLM separation system, heavy metals such as cadmium and copper, were successfully recovered from the WPA: average fluxes (in mol/m2sec) to the strip phase were 3.7 × 10-7 and 6.7 × 10-7. Satisfactory dynamic selectivity to copper (≈16) was found. The transfer of iron and zinc species to the strip phase was below detection levels during the 144 hrs of the AHLM experiment. Contamination of the feed and strip solutions by PVSA was not observed during the 500 hrs of processing. The membranes were completely regenerable and used repeatedly. In comparison with the HLM and other liquid membrane systems, the AHLM can potentially provide many operational, economic and environmental advantages, some of them being higher transport rates, low carrier losses and low contamination of the feed and strip solutions by water-soluble polymers, long membrane lifetime, ambient temperature, low energy requirements and chemical consumption, no special requirements for membrane resistance in organic solvents, and fewer limitations on the variability of membrane pore sizes, etc.

Pertraction of cadmium and zinc ions using a supported liquid membrane impregnated with different carriers

2013 ◽  
Vol 67 (4) ◽  
Author(s):  
Mohammad Peydayesh ◽  
Gholam Esfandyari ◽  
Toraj Mohammadi ◽  
Eskandar Alamdari
Keyword(s):  
Phosphoric Acid ◽  
Carrier Concentration ◽  
Metal Ion ◽  
Liquid Membrane ◽  
Feed Solution ◽  
Supported Liquid Membrane ◽  
Optimum Conditions ◽  
Feed Concentration ◽  
Experimental Conditions ◽  
Cyanex 302

AbstractAn experimental study on the removal of Cd2+ and Zn2+ through a supported liquid membrane using a mixture of mono-(2-etylhexyl) ester of phosphoric acid (M2EHPA) and bis-(2-etylhexyl) ester of phosphoric acid (D2EHPA) as carriers is presented. Parameters affecting the Cd2+ and Zn2+ pertraction such as feed concentration, carrier concentration, pH of the stripping phase, and TBP (tributyl phosphate) concentration were analyzed using the Taguchi method. Optimal experimental conditions for Cd2+ and Zn2+ pertraction were obtained using the analysis of variance (ANOVA) after a 6 h separation with the initial feed concentration of 8.9 × 10−4 mol L−1, carrier concentration of 20 vol. %, TBP concentration of 4 vol. %, and pH of 0.5. Then, under optimum conditions, a comparison of M2EHPA, D2EHPA, and bis-(2,4,4-trimethylpentyl)monothiophosphinic acid (Cyanex 302) was performed. Effective pertraction of Cd2+ and Zn2+ using these carriers was observed in the following order: mixture of M2EHPA and D2EHPA, D2EHPA, Cyanex 302. It was also found that the presence of one metal ion in the feed solution reduces the pertraction rate of the other one.

CLINICAL INVESTIGATIONS OF A LONG-ACTING OESTRIOL (POLYOESTRIOL PHOSPHATE)

1961 ◽  
Vol 38 (1) ◽  
pp. 73-87 ◽  
Author(s):  
Christian Lauritzen ◽  
Semih Velibese
Keyword(s):  
Side Effects ◽  
Phosphoric Acid ◽  
Quantitative Data ◽  
Water Soluble ◽  
Cholesterol Concentration ◽  
Experimental Investigations ◽  
Clinical Investigations ◽  
Prolonged Duration ◽  
High Doses ◽  
Long Acting

ABSTRACT A description is given of experimental investigations and preliminary clinical experience with the long-acting oestriol compound polyoestriol phosphate – a water-soluble polymere of oestriol and phosphoric acid. The compound seems to exert all the physiologically important effects of oestriol. Even with high doses the hormone causes no proliferation of the endometrium and no withdrawal bleeding. It has no untoward effect on metabolism. It decreases slightly the cholesterol concentration (to the extent of ⅓–⅕ of the effect produced by long-acting oestradiol esters). The compound has a wide therapeutic range. No side-effects have been observed. Doses of 10 mg or more have a prolonged duration. Additional prolongation of the effect is largely dependent on dosage. To ensure an effect lasting for 4 weeks 40 mg polyoestriol phosphate (corresponding with 30 mg oestriol) is required – an amount which roughly corresponds with physiological quantitative data. The compound, which involves an interesting new principle of prolongation, was most effectively used in the treatment of menopausal symptoms and genital organic disorders. For these indications it can be recommended without reservation.

scholarly journals Insights on Molecular Characteristics of Hydrochars by 13C-NMR and Off-Line TMAH-GC/MS and Assessment of Their Potential Use as Plant Growth Promoters

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1026 ◽  
Author(s):  
Laís G. Fregolente ◽  
João Vitor dos Santos ◽  
Giovanni Vinci ◽  
Alessandro Piccolo ◽  
Altair B. Moreira ◽  
...  
Keyword(s):  
Plant Growth ◽  
Phosphoric Acid ◽  
13C Nmr ◽  
Chemical Properties ◽  
Water Soluble ◽  
Molecular Characteristics ◽  
Initial Growth ◽  
Growth Promoters ◽  
Molecular Features ◽  
Potential Use

Hydrochar is a carbon-based material that can be used as soil amendment. Since the physical-chemical properties of hydrochar are mainly assigned to process parameters, we aimed at evaluating the organic fraction of different hydrochars through 13C-NMR and off-line TMAH-GC/MS. Four hydrochars produced with sugarcane bagasse, vinasse and sulfuric or phosphoric acids were analyzed to elucidate the main molecular features. Germination and initial growth of maize seedlings were assessed using hydrochar water-soluble fraction to evaluate their potential use as growth promoters. The hydrochars prepared with phosphoric acid showed larger amounts of bioavailable lignin-derived structures. Although no differences were shown about the percentage of maize seeds germination, the hydrochar produced with phosphoric acid promoted a better seedling growth. For this sample, the greatest relative percentage of benzene derivatives and phenolic compounds were associated to hormone-like effects, responsible for stimulating shoot and root elongation. The reactions parameters proved to be determinant for the organic composition of hydrochar, exerting a strict influence on molecular features and plant growth response.

scholarly journals Adsorption of heavy metals by road deposited solids

2013 ◽  
Vol 67 (11) ◽  
pp. 2622-2629 ◽  
Author(s):  
Chandima Gunawardana ◽  
Ashantha Goonetilleke ◽  
Prasanna Egodawatta
Keyword(s):  
Heavy Metals ◽  
Kinetic Studies ◽  
Field Studies ◽  
Water Soluble ◽  
Trivalent Cation ◽  
Urban Road ◽  
High Charge Density ◽  
Road Surfaces ◽  
Adsorption Desorption ◽  
Exchangeable Form

The research study discussed in the paper investigated the adsorption/desorption behaviour of heavy metals commonly deposited on urban road surfaces, namely, Zn, Cu, Cr and Pb, for different particle size ranges of solids. The study outcomes, based on field studies and batch experiments, confirmed that road deposited solids particles contain a significantly high amount of vacant charge sites with the potential to adsorb additional heavy metals. Kinetic studies and adsorption experiments indicated that Cr is the most preferred metal element to associate with solids due to the relatively high electronegativity and high charge density of trivalent cation (Cr3+). However, the relatively low availability of Cr in the urban road environment could influence this behaviour. Comparing total adsorbed metals present in solids particles, it was found that Zn has the highest capacity for adsorption to solids. Desorption experiments confirmed that a low concentration of Cu, Cr and Pb in solids was present in water-soluble and exchangeable form, whilst a significant fraction of adsorbed Zn has a high likelihood of being released back into solution. Among heavy metals, Zn is considered to be the most commonly available metal among road surface pollutants.

Phosphoric acid purification sludge: Potential in heavy metals and rare earth elements

2019 ◽  
Vol 83 ◽  
pp. 46-56 ◽  
Author(s):  
Marzougui Salem ◽  
Radhia Souissi ◽  
Fouad Souissi ◽  
Noureddine Abbes ◽  
Jacques Moutte
Keyword(s):  
Heavy Metals ◽  
Rare Earth ◽  
Phosphoric Acid ◽  
Rare Earth Elements

scholarly journals The Role of the Humic Substances in the Fractioning of Heavy Metals in Rodrigo de Freitas Lagoon, Rio de Janeiro - Brazil

2013 ◽  
Vol 85 (4) ◽  
pp. 1289-1301 ◽  
Author(s):  
ESTEFAN M. DA FONSECA ◽  
JOSE A. BAPTISTA NETO ◽  
JOHN MCALISTER ◽  
BERNARD SMITH ◽  
MARCOS A. FERNANDEZ ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Organic Matter ◽  
Rio De Janeiro ◽  
Water Soluble ◽  
Metal Partitioning ◽  
Fine Grain ◽  
Soluble Phase ◽  
The City ◽  
South Zone

One of the main results of the processes related to urbanization is the contamination of the adjacent water bodies. Inserted in this context, the Rodrigo de Freitas lagoon is situated in the south zone of the city of Rio de Janeiro. This ecosystem receives several inputs containing all sorts of pollutants, including heavy metals. The present work aimed to study the partitioning of heavy metals in the sediments of Rodrigo de Freitas and the influence of organic matter in this fractionation dynamic. The results of these analyses presented the contents of organic matter as an important metal-capturing agent. Fractionation of organic matter resulted in a predominance of humine. Heavy metal partitioning showed that the metals bound by the water-soluble phase have no significant concentrations. Special features such as, reducing sediment, high levels of organic matter and fine grain size have transformed this ecosystem in an effective deposit of pollutants, where heavy metals are not available in easily reactive fractions.

Sign in / Sign up

Export Citation Format

Share Document