Selective Co(ii) removal from aqueous media by immobilizing silver nanoparticles within a polymer-matrix through a formaldehyde cross linking agent

RSC Advances ◽  
2015 ◽  
Vol 5 (30) ◽  
pp. 23340-23349 ◽  
Author(s):  
S. Siva ◽  
S. Sudharsan ◽  
R. Sayee Kannan

A novel hybrid cation exchange resin was developed by encapsulating AgNPs within a macroporous phenol–formaldehyde cation exchanger for the removal of cobalt from aqueous solution.

An equation for the flux of electrolyte through a water-swollen cation-exchange resin membrane separating two solutions of the same electrolyte at different concentrations is derived on the basis of several assumptions regarding the physical nature of a swollen resinous exchanger. The complete flux equation contains three terms, one determined by the concentration difference across the membrane, another determined by the variation of the activity coefficient of the electrolyte with concentration in the membrane and a third concerned with the rate of osmotic or hydrostatic flow through the membrane. If ions in the resin are transported entirely in an internal aqueous phase, the mobilities required for the flux equation can be related to mobilities in aqueous solution and to the volume fraction of resin in the swollen membrane. The treatment is readily extended to anion exchangers.


2020 ◽  
Vol 61 (2) ◽  
pp. 139-144
Author(s):  
Svetlana E. Pratskova ◽  
◽  
Aleksandr V. Kolesnikov ◽  
Alena O. Kuvaeva ◽  
Oksana U. Kuznetsova ◽  
...  

One of the main tasks of environmental protection enterprises is to reduce industrial effluents. Industrial effluents with a content of sodium chloride 24-25% and sodium sulfate 1.5-3.0% are formed at one of the plants. The high content of sodium chloride in the effluent allowed us to make an assumption about the possibility of their use in the regeneration of Na-cation exchanger in the process of water treatment for vapor-vapor cooling of operating metallurgical units. The aim of the work was to determine the feasibility of using industrial salt effluents in the water treatment process while ensuring optimal conditions for the operation of Na-cation exchanger. In the process of water treatment used the method of removing impurities from water - cationization. This method is applied to soften water and is of independent importance in the preparation of additional water for low pressure boilers and make-up water for heating networks, if the source water has low alkalinity. The object of the study is a strongly acidic cation exchanger in the Na-form (Purolite PPC-100Na) designed to soften process water. In the course of the regeneration of cation exchange resin with a sodium sulfate-containing salt solution, the concentration of the latter should be controlled - this is due to the high exchange capacity and the real danger of the formation of the gypsum layer. The volume of spent regeneration solution (OPP) will contain sparingly soluble calcium sulfate and soluble magnesium sulfate. Under certain conditions, most of the calcium sulfate can be separated from the ORP in the form of a suspension of a two-water compound and detached from the solution. Laboratory studies were conducted on the effect of a solution of NaCl salt (24-25%) with an admixture of sodium sulfate (1.5-3.0%) on the total and working exchange capacity of cation exchange resin. In order to reduce the salt background of the regenerated solution, studies were carried out on the use of a 10% NaCl salt solution with an admixture of sodium sulfate (1.5-3.0%) on the static, dynamic and full dynamic working exchange capacity of cation exchange resin (SOE, DOE and PDOE). We used the methods of alkalimetric and complexometric titration to control the capacity value of the cation. It was determined that the numerical values of the DOE and PDOE of the studied cation exchanger during its regeneration with a saline solution of sodium chloride with a content of 1.5-3.0% sodium sulfate vary in the range of 1.96-1.22 and 2.58-1.89 mEq/g dry resin, respectively.


2016 ◽  
Vol 718 ◽  
pp. 67-71
Author(s):  
Nopphorn Chanthapon ◽  
Pornsawai Praipipat ◽  
Sudipta Sarkar ◽  
Surapol Padungthon

This study is aimed to synthesize, characterize and validate the performance of a novel hybrid nanoadsorbent for selective removal of lead from a battery manufacturing wastewater. The hybrid nanosorbent, named as HCIX-Fe, was prepared by impregnating hydrated Fe (III) oxide (HFO) nanoparticles inside polymeric cation exchange resin containing negatively charged sulfonic acid (-SO3-) fixed functional groups. HCIX-Fe was characterized by SEM-EDX and XRD to confirm the distribution and determination of phase of HFO dispersed inside the hybrid nanosorbent. Fixed-bed column runs with HCIX-Fe beads were carried out using wastewater from a battery manufacturing plant. The wastewater had a pH of 1.8 and contained of 3.5 mg/L of Pb2+ coexisted with 250 mg/L Ca2+ ions. The results have shown that HCIX-Fe column could treat lead-contaminated water up to 6,500 bed volumes (BVs) before the occurrence of breakthrough concentration of 0.2 mg/L Pb2+ resulting in a removal capacity of 6.85 mg Pb2+/ml of the HCIX-Fe bed. Under similar condition, adsorbent columns with cation exchange resin (C100), granulated activated carbon (GAC) and granulated activated carbon impregnated with HFO (GAC-Fe), could treat the same wastewater only until 400, 900 and 1,500 BVs, respectively. When compared with the parent adsorbents, impregnation by HFO greatly enhanced the Pb2+ removal capacity of C100 and GAC by 1,625% and 167%, respectively. Both HFO and high density of sulfonic acid (-SO3-) in the host cation exchanger are individually capable of selective removal of Pb2+ ions; however the hybrid material demonstrated a synergistic effect for Pb2+ removal through the Donnan Membrane effect. Due to amphoteric behavior of HFO, the HCIX-Fe could be regenerated and reused with 10 BVs of 2% HNO3 and 1% FeCl3·6H2O solution.


2009 ◽  
Vol 167 (1-3) ◽  
pp. 915-926 ◽  
Author(s):  
Nadir Dizge ◽  
Bülent Keskinler ◽  
Hulusi Barlas

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