Sorption of Ni, Zn and Cd on Sepiolite

Clay Minerals ◽  
1985 ◽  
Vol 20 (4) ◽  
pp. 525-527 ◽  
Author(s):  
E. Helios-Rybicka

The ability of clay minerals to adsorb heavy metal cations is an important property in the context of the increasing contamination of the aquatic environment and soils by toxic waste. Laboratory studies of the sorption of heavy metals by clays have mostly been carried out using montmorillonite and illite (Chester, 1965; Egozy, 1970; Bourg & Filby, 1974; Helios-Rybicka & Schoer, 1982), less frequently for kaolinite, and only rarely for mixed-layer illite-montmorillonite (Helios-Rybicka, 1983) and the fibrous clay minerals sepiolite and palygorskite. This note describes the sorptive behaviour of sepiolite towards Ni, Zn and Cd.

2010 ◽  
Vol 61 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Slávka Andrejkovičová ◽  
Martin Pentrák ◽  
L'uboš Jankovič ◽  
Peter Komadel

Sorption of heavy metal cations on rhyolitic and andesitic bentonites from Central SlovakiaThe main purpose of this work was to determine adsorption characteristics of heavy metal cations on two Slovak bentonites. Adsorption of Pb2+, Zn2+, Cu2+and Cd2+on Jelšový Potok (JP) and Lieskovec (L) bentonites was studied by the batch equilibration technique using solutions of different concentrations. Higher smectite content (81 mass %) and higher cation exchange capacity (CEC) (105 mmol M+/100 g) of JP bentonite cause higher adsorption of all heavy metals in comparison with L bentonite. JP adsorbed heavy metals in the order Pb2+» Cd2+> Zn2+> Cu2+while sorption on L was slightly different, Pb2+» Cd2+> Cu2+≥ Zn2+. The Freundlich model of adsorption is more appropriate for adsorption of Pb2+and Cd2+while lower uptake of Cu2+and Zn2+is better described by the Langmuir model. Negative ΔG° values indicate that the adsorption process of all cations on both bentonites is feasible, spontaneous and exothermic. The decrease in thed001spacings from 14.8-14.9 Å in natural dominantly Ca2+-saturated samples to 13.2-12.6 Å for both bentonites saturated with four heavy metal cations shows the effect of less hydrated exchangeable cations on interlayer spacing. Jelšový Potok bentonite of higher montmorillonite content and greater CEC is the more effective candidate for removal of Pb2+, Zn2+, Cu2+and Cd2+from waste water than Lieskovec bentonite.


1996 ◽  
Vol 34 (11) ◽  
pp. 193-200 ◽  
Author(s):  
A. U. Baes ◽  
S. J. P. Umali ◽  
R. L. Mercado

Potentiometric titration experiments were carried out to determine the relative ability of sodium and different heavy metal cations in replacing protons from ionogenic sites of a modified coconut coir cation exchanger. The relative preference for the cations follow the sequence: Na ≪ Ca(II) < Mn(II) < Ni(II) < Cu (II) < Pb(II). This preferential series was confirmed by determining the concentrations of the divalent cations and sodium which were adsorbed by the material during the titration process. Adsorption isotherms at pH 4 and pH 6 were obtained to determine the Langmuir adsorption constants for the heavy metal cations. The adsorbent material adsorbed high amounts of Pb(II), Cu(II) and Ni(II) (in decreasing order) from solutions whose concentrations were comparable to those of wastewaters. Our results show that the modified coconut coir cation exchanger has good potential as an adsorbent of heavy metals in industrial wastewaters.


2016 ◽  
Vol 11 (10) ◽  
pp. 3870-3874
Author(s):  
Lassaad Baklouti

The synthesis and the binding properties of novel phthalonitrile derivatives 1-3 towards metal cations have been described in this paper. The complexation and extraction of some transition and heavy metal cations have been followed by UV-visible spectrophotometry absorption in methanol. The conductivity studies have been used in order to confirm complex’s stoichiometries. The treatment of UV spectra by digital program showed the formation of ML (with ML2 in some cases) (M=metal, L=ligand) species. Beyond the discussion of the stability profiles of complexes particular attention is paid to the selectivity towards Cu2+ in the 1st sequence of transition metal cations and towards Hg2+ in the sequence of heavy metal cations.


2019 ◽  
Vol 4 (1) ◽  
pp. 19-22
Author(s):  
Vika Ayu Devianti ◽  
Anisa Rizki Amalia

ABSTRAKVitamin C berperan penting dalam mempertahankan daya tahan tubuh. Vitamin C mudah teroksidasi dan tidakstabil dalam bentuk larutan. Vitamin C banyak ditemukan dalam buah – buahan, diantaranya adalah apel danstroberi. Apel dan stroberi ini sering diolah dalam bentuk minuman sari buah melalui proses ekstraksi osmosis. Tujuan penelitian ini adalah untuk mengetahui pengaruh lama waktu osmosis (30 dan 60 menit) dan penambahan gula 10% terhadap kandungan vitamin C dalam minuman sari buah apel dan stroberi. Penambahan gula 10% mampu memperkecil penurunan kadar vitamin C dalam minuman sari buah. Penurunan kadar vitamin C pada sampel sari buah stroberi tanpa penambahan gula adalah 18,7% pada menit ke-30 dan 37,5% pada menit ke-60, sedangkan penambahan gula 10% mengalami penurunan sebesar 2,7% pada menit ke-30 dan 7,9% pada menit ke-60. Penurunan kadar vitamin C pada sampel sari buah apel tanpa penambahan gula adalah 24,2% pada menitke-30 dan 41,6% pada menit ke-60, sedangkan penambahan gula 10% mengalami penurunan sebesar 10,6% pada menit ke-30 dan 21,4% pada menit ke-60.Kata kunci: Vitamin C, sukrosa, minuman sari buah, apel, strawberry, osmosis ABSTRACTVitamin C plays an important in human body. Vitamin C is easily degraded by heat, light, oxygen, and heavy metal cations. Vitamin C mostly found in fruits, such as strawberry and apple. Generally strawberry and apple are processed into fruit juice by adding sugar using osmosis extraction. The objective of this research is to findout the effect of osmosis time and sugar addition towards the vitamin C level in strawberry and apple juice. The result showed that sugar addition can affect the vitamin C level in strawberry and apple juice. Sugars can decrease the oxygen solubility causing less oxygen availability for oxidation of vitamin C. The diminish of vitamin C content in apple juice with sugar addition were 10,6% and 21,4% for 30 and 60 minutes of osmosis time; while strawberry juice with sugar addition able to lowering vitamin C level until 18,7% and 37,5% for 30 and 60 minutes of osmosis time.Keywords: Vitamin C, sucrose, apple juice, strawberry juice, osmosis,


Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2150 ◽  
Author(s):  
M.A. Martín-Lara ◽  
M. Calero ◽  
A. Ronda ◽  
I. Iáñez-Rodríguez ◽  
C. Escudero

Bisphenol A (BPA) is an extensively produced and consumed chemical in the world. Due to its widespread use, contamination by this pollutant has increased in recent years, reaching a critical environmental point. This work investigates the feasibility of bisphenol A adsorption from industrial wastewater solutions, testing the reduction of bisphenol A in synthetic solutions by a commercial activated carbon, AC-40, in batch mode. Besides, mixtures of bisphenol A and different heavy metal cations were also studied. So far, no works have reported a complete study about bisphenol A removal by this activated carbon including the use of this material to remove BPA in the presence of metal cations. First, adsorption experiments were performed in batch changing pH, dose of adsorbent, initial bisphenol A concentration and contact time. Results showed greater retention of bisphenol A by increasing the acidity of the medium. Further, the percentage of bisphenol A adsorbed increased with increasing contact time. The selected conditions for the rest of the experiments were pH 5 and a contact time of 48 h. In addition, an increase in retention of bisphenol A when the dose of adsorbent increased was observed. Then, specific experiments were carried out to define the kinetics and the adsorption isotherm. Equilibrium data were adequately fitted to a Langmuir isotherm and the kinetics data fitted well to the pseudo-second-order model. The maximum adsorption capacity provided by Langmuir model was 94.34 mg/g. Finally, the effect of the presence of other heavy metals in water solution on the adsorption of bisphenol A was analyzed. Binary tests revealed competition between the adsorbates and a significant selectivity toward bisphenol A. Finally, the study of the adsorption performance in three consecutive adsorption–desorption cycles showed efficiencies higher than 90% in all cycles, indicating that the activated carbon has good reusability.


2020 ◽  
Vol 381 ◽  
pp. 122656 ◽  
Author(s):  
Quan Chen ◽  
Zhenya Tang ◽  
Hao Li ◽  
Min Wu ◽  
Qing Zhao ◽  
...  

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