Lead and Cadmium Removal by Ion Exchange

1992 ◽  
Vol 25 (1) ◽  
pp. 133-138 ◽  
Author(s):  
E. Maliou ◽  
M. Malamis ◽  
P. O. Sakellarides

The ion exchange properties of the zeolites can be used to remove certain ions from the effluents. In this work a natural clinoptilolite has been examined systematically in order to evaluate whether this low cost mineral can be employed for the removal of the metals lead and cadmium which are very toxic, even at very low concentrations. Studies were performed under various conditions such as presence of different cations (Pb, Cd, Na), zeolite grain size, solution temperature. The results obtained indicate that the size of the zeolite does not affect the actual metal uptake at the equilibrium point, but the metal removal is greatly affected when the contact of the solid/liquid phases is short, a very essential parameter for the waste water treatment. For a short contact time the metal quantities removed using small grain size is nearly doubled. The same pattern is followed at higher temperatures, though a slight increase is observed for both zeolite grain sizes and both metals, lead and cadmium. At equilibrium half of the theoretical exchange capacity of the zeolite is used, approximately 1.4 meq/g for lead and 1.1 meq/g for cadmium. The kinetic curves show very clearly the selectivity of the zeolite for the Pb ions but also significant amounts of cadmium are removed as well.

Author(s):  
Thounaojam Thomas Meetei ◽  
Yumnam Bijilaxmi Devi ◽  
Thounaojam Thorny Chanu

Ion exchange is the interchange of equivalent amount of ions from the solution with ions which are swarming in a boundary of charged surface in equilibrium. It is developed due to the presence of charge in the soil colloids or layer lattice clay minerals. The source of charge developed in the colloidal surface site of soil is mainly from two processes viz. isomorphous substitution and pH dependent charge. The charge can be positive or negative due to the exchange reaction in the layer lattice. The ion exchange capacity is the sum of cation exchange capacity (CEC) and anion exchange capacity (AEC). It depends on the types of soil and the amount of charge present in the layer lattice colloidal structure. With high negative charge in the lattice surface the CEC increases and with positive charge the AEC. Ions with higher charge have larger affinity to adsorbed more strongly than lower. Ion exchange capacity in soil has the ability to retained more nutrients in the form of cations or anions making available to plant for a long time which improved the fertility of soil. Leaching loss of different nutrients from the soil is reduced by holding different ions. Ion exchange processes have been widely used for heavy metal removal for waste water treatment and water purification because of its high remedial capacity, high removal efficiency and fast kinetic. Due to its applications in agriculture, environmental management, industries, waste water treatment in mining industries,  laboratory, nanotechnology, geotechnical and other soil reclamation processes it is considered as the second most important reaction in the globe after photosynthesis.


2015 ◽  
Vol 5 (2) ◽  
pp. 33-38
Author(s):  
Quang Thai Le ◽  
Minh Tuan Pham ◽  
Nguyen Quynh Trinh ◽  
Khac Tuan Vu ◽  
Hong Ha Nguyen ◽  
...  

Ion exchange is one of the most popular techniques for recovery and purification of uranium from sulfuric acid leaching solution, especially for recovery of uranium from a low uranium containing solutions. Resins commonly used are strong base or weak base anion resins with amine functional group. The anionic form of resins may be NO3-, Cl- , SO­42- or OH-. The selection of  a resin depends on the uranium total exchange capacity, selectivity and the cost. The previous studies often use Amberlite IRA-420 for concentration and purification of uranium solution from Pa Lua sandstone ores. This is a good and suitable resin but high price. To diversify the resins and reduce the costs, instead of IRA-420, the authors tested two commercial resins Indion GS300 (India) and Purolite A400 (UK) in the processing of uranium solution from sandstone ores. The results showed that the uranium total exchange capacity of  these resins is only about 80 - 85% over  Amberlite IRA-420, but these resins should be able to be used instead of Amberlite IRA-420 due to their low cost and availability in Vietnam.


Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 406 ◽  
Author(s):  
Abdulaziz N. Amro ◽  
Mohammad K. Abhary ◽  
Muhammad Mansoor Shaikh ◽  
Samah Ali

In recent years, the interest in waste water treatment increased to preserve the environment. The objective of this study is the removal of lead and cadmium ions from aqueous solution by treated Phragmites biomass (TPB). TPB was characterized by using Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDS) which indicates the presence of functional groups that may be responsible of metal adsorption such as hydroxyl, carbonyl, sulfonate and carboxylate. Characterization by scanning electron microscopy (SEM) and surface area analysis using the Brunauer–Emmett–Teller method (BET) illustrated that TPB is nonporous with a small surface area. The influences of various experimental factors were investigated; the proposed method recommended the extraction of Pb+2 and Cd+2 metal ions by TPB at pH 5.0. A contact time of 60 and 45 min was required for the adsorption 50 mL (50 ppm) Pb+2 and Cd+2 respectively to reach equilibrium when 0.10 g TPB was used. The optimum TPB dosage was 0.20 g for adsorption both metal ions when adsorbate solution was 50 mL (50 ppm). Particle sizes of 0.125–0.212 mm showed the best metal ion removal of both metal ions. Thermodynamic study illustrated that both metal ions correlate more with Langmuir isotherm. Furthermore, chemisorption of Pb+2 and Cd+2 on TPB was more likely according to kinetic study data.


1997 ◽  
Vol 35 (7) ◽  
pp. 89-95 ◽  
Author(s):  
Aloysius U. Baes ◽  
Tetsuji Okuda ◽  
Wataru Nishijima ◽  
Eiji Shoto ◽  
Mitsumasa Okada

The adsorption of nitrate, chromium (VI), arsenic (V) and selenium (VI) anions in an amine modified coconut coir (MCC-AE : with secondary and tertiary amine functionality) were studied to determine the capability of this easily prepared and low-cost material in removing typical groundwater anion contaminants. Batch adsorption-ion exchange experiments were conducted using 200 mg MCC-AE, initially containing chloride as the resident anion, and 50 ml of different anion-containing water of varying concentrations. It is presumed, at this low pH, that only SeO42− remained as a divalent anion, while monovalent species H2AsO4− and HCrO4− predominated in their respective exchanging ion solutions. The adsorption data were fitted using the Freundlich equation and maximum adsorption for each anion was estimated using their respective Freundlich equation constants. MCC-AE exhibited preference for divalent Cr (VI) and Se (VI) anions compared with the Cl− resident ion. Maximum As (V) adsorption was 0.086 mmol/g, while maximum adsorption of Cr (VI), NO3− and Se (VI) anions was 0.327 mmol/g, 0.459 mmol/g, and 0.222 mmol/g, respectively. The ion exchange capacity of MCC-AE is estimated, based on its exchange capacity for nitrate, to be within 0.46 mmol of positive charges per gram. Similar adsorption experiments were conducted for comparison using commercial chloride-form Amberlite IRA-900 strong base (quaternary amine functionality) anion exchanger, with an exchange capacity of 4.2 meq/g. Maximum adsorption of the different ions in IRA-900 was about 3 times higher for NO3−, 9 times higher for Se (VI), 10 times higher for As (V) and 9 times higher for Cr (VI), than that in MCC-AE. Differences in the ion exchange behavior of MCC-AE and IRA-900 were probably due to the different amine functionalities in the two exchangers. The results suggest that MCC-AE may be used as a low-cost alternative adsorbent/ion exchanger for treatment of anion contaminants in groundwater.


1999 ◽  
Vol 39 (10-11) ◽  
pp. 115-122 ◽  
Author(s):  
S. K. Ouki ◽  
M. Kavannagh

This paper assesses the potential of natural zeolite utilization as a low-cost in exchange material for heavy metals removal. Two natural zeolites, clinoptilolite and chabazite, have been evaluated with respect to their selectivity and removal performance for the treatment of effluents contaminated with mixed heavy metals (Pb, Cd, Cu, Zn, Cr, Ni and Co). The effects of relevant parameters such as chemical treatment, metals concentration, pH, and presence of competing ions were examined. The results showed that the received zeolites contained exchangeable K, Ca and Na ions, but exposing them to concentrated NaCl solutions converted them to a homoionic state in the Na form which improved their exchange capacity. Clinoptilolite and chabazite exhibited different selectivity profiles for all metals studied except for Pb for which both zeolites performed exceptionally well. The results also showed that chabazite exchange capacity is superior to that of clinoptilolite mainly due to the higher Al substitution of Si which provides chabazite with a negative framework favourable to higher exchange capability. The pH was found to have an effect on metal removal as it can influence both the character of the exchanging ions and the zeolite itself. Overall, the removal mechanism was controlled by ion exchange and precipitation was proven negligible.


Author(s):  
Enas A. Almadani ◽  
Farah Haron ◽  
Dala M Ibrahim

Clay and clay modified catalysts have been widely used to catalyze various types of organic reactions such as esterification reactions, isomerization reactions, cyclization reactions, oxidation of alcohols, dehydrogenation, epoxidation and several more. Due to its favorable properties such as low cost, thermal stability, selectivity, large surface area, ion exchange capacity, easily separated, as well as environmental friendly. This paper reviewed some recent studies on the using of clay and modified clay as catalyst for the production of esters.


2015 ◽  
Vol 72 (4) ◽  
Author(s):  
Mohd Ismid Mohd Said ◽  
Shaikhah Sabri ◽  
Shamila Azman

Contamination of metals in aquatic environment is a worldwide problem because of its toxicity and capability to accumulate in biological chain, as well as persistence in the natural environment. Therefore various expensive technologies have been applied to treat metal-polluted water. In Malaysia there are abundance of banana species available which could provide cheap, low cost and environmental friendly bio-materials. Preliminary study was conducted on two species of banana i.e. Musa balbisiana (Nipah) and Musa acuminata (Kapas). The banana peels were washed, dried and grounded into various range of particle sizes (0.20–1.18 mm). The ability of the adsorbents were determined by agitation of 1.0 g banana peel and 100 ml of cadmium standard solution at the concentration of 100 mg/L. Musa balbisiana showed the highest removal of cadmium at 89.58% from the initial concentration compared to Musa acuminate with the particle size of 0.30-0.60 mm. Adsorption equilibrium data are well described by Langmuir isotherm model. The result also shows that different species have different capabilities to adsorb metal. Hence, their potential as bio-adsorbent could be further be examined for metal removal from wastewater.


Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2991
Author(s):  
Carmelo Lo Vecchio ◽  
Alessandra Carbone ◽  
Stefano Trocino ◽  
Irene Gatto ◽  
Assunta Patti ◽  
...  

Tandem photo-electro-chemical cells composed of an assembly of a solid electrolyte membrane and two low-cost photoelectrodes have been developed to generate green solar fuel from water-splitting. In this regard, an anion-exchange polymer–electrolyte membrane, able to separate H2 evolved at the photocathode from O2 at the photoanode, was investigated in terms of ionic conductivity, corrosion mitigation, and light transmission for a tandem photo-electro-chemical configuration. The designed anionic membranes, based on polysulfone polymer, contained positive fixed functionalities on the side chains of the polymeric network, particularly quaternary ammonium species counterbalanced by hydroxide anions. The membrane was first investigated in alkaline solution, KOH or NaOH at different concentrations, to optimize the ion-exchange process. Exchange in 1M KOH solution provided high conversion of the groups, a high ion-exchange capacity (IEC) value of 1.59 meq/g and a hydroxide conductivity of 25 mS/cm at 60 °C for anionic membrane. Another important characteristic, verified for hydroxide membrane, was its transparency above 600 nm, thus making it a good candidate for tandem cell applications in which the illuminated photoanode absorbs the highest-energy photons (< 600 nm), and photocathode absorbs the lowest-energy photons. Furthermore, hydrogen crossover tests showed a permeation of H2 through the membrane of less than 0.1%. Finally, low-cost tandem photo-electro-chemical cells, formed by titanium-doped hematite and ionomer at the photoanode and cupric oxide and ionomer at the photocathode, separated by a solid membrane in OH form, were assembled to optimize the influence of ionomer-loading dispersion. Maximum enthalpy (1.7%), throughput (2.9%), and Gibbs energy efficiencies (1.3%) were reached by using n-propanol/ethanol (1:1 wt.) as solvent for ionomer dispersion and with a 25 µL cm−2 ionomer loading for both the photoanode and the photocathode.


2009 ◽  
Vol 60 (2) ◽  
pp. 293-300 ◽  
Author(s):  
A. N. Módenes ◽  
J. M. T. de Abreu Pietrobelli ◽  
F. R. Espinoza-Quiñones

In this work the removal potential on Cd2+  by the non-living Egeria densa biomass has been studied. The influence of the metal solution pH, the plant drying and the metal solution temperature, and biosorbent grain size was previously studied in batch systems. The cadmium adsorption rate has increased when the pH was increasing, but at pH 5, the cadmium precipitation has begun to occur, avoiding such high pH values in other tests. The cadmium removal was around 70% at 30°C biomass dried and solution temperatures, assuming as the best temperature conditions. No significant influence was observed in cadmium removal due to the grain size effect. The biosorption kinetic data were well fitted by a pseudo-second order model. The equilibrium time in experiments was around 45 min with a 70% Cd removal. The equilibrium data at pH 5 were described rather better by the Langmuir isotherm than the Freundlich one, with an adsorption rate and maximum metal content values of 0.40 L  g−1 and 1.28 meq  g−1, respectively, for Langmuir model. The kinetic parameter values are near to other biosorbents, indicating that the macrophytes E. densa could be used as biosorbent material in industrial effluent treatment system.


Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1074
Author(s):  
Steven A Lucas ◽  
Charles CC Lee ◽  
Eric Love

Filter media (FM) sourced from recycled organic and mineral materials offer an effective and low cost means of treating urban stormwater. Using recycled materials rather than the increasingly scarce source of virgin materials (typically sandy loam soil) can ensure a sustainable and long-term economy and environment. This paper presents the results from the laboratory analysis and mathematical modelling to highlight the performance of recycled organic and mineral materials in removing nutrients and metals from stormwater. The analysis included the physical and chemical characterisation of particle size distribution, saturated hydraulic conductivity (Ksat), bulk density, effective cation exchange capacity, and pollutant removal performance. The design mixes (DM), comprising a combination of organic and mineral materials, were characterised and used to develop/derive the modelling design within the Model for Urban Stormwater Improvement Conceptualisation (MUSIC v6). Comparison is made to the Adoption Guidelines for Stormwater Biofiltration Systems—Summary Report which were based on the Facility for Advancing Water Biofiltration (FAWB) guidelines to assist in the development of biofiltration systems, including the planning, design, construction, and operation of those systems. An observed outcome from over two decades of biofiltration guideline development has been the exclusion of alternative biofilter materials due to claims of excessive leaching. Results from this study indicate that high nutrient and metal removal rates can be achieved over a range of hydraulic conductivities using design mixes of recycled organic and mineral materials that have a demonstrated equivalence to existing guideline specifications.


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