Removal of cadmium from aqueous solutions using clinoptilolite: Influence of pretreatment and regeneration

Gedik, Kadir
İmamoğlu, İpek
In this study, Cd removal from aqueous solutions via clinoptilolite was investigated in terms of the effect of pretreatment and regeneration. Four different chemicals (NaCl, KCl, CaCl2 and HCl) were tested for this purpose. Samples treated by a total of 20 bed volume (BV) of 1 M NaCl solution prepared in tap water with no pH adjustment were found to perform satisfactorily. Five exhaustion and regeneration cycles were then carried out, revealing an increasing Cd removal capacity, coupled with constant Cd elution efficiency in progressing cycles. Furthermore, the change of pH and the presence of exchangeable (Na, K, Ca and Mg) and framework cations (Si and Al) in the aqueous phase were investigated. Subsequently, these were discussed in terms of progressive conversion of clinoptilolite to its homoionic Na-form, and the presence of different Cd removal mechanisms in the system. This study emphasizes the potential of clinoptilolite to be a part of sustainable wastewater treatment technologies, enabling the recovery of both the sorbent and the metal, via demonstration of effective Cd removal and clinoptilolite recovery, besides successful concentration of metal in the regenerant solution.


Removal of Ni(II) Ions From Aqueous Solutions Using Activated-Carbon Prepared From Olive Stone by ZnCl2 Activation
The aim of this study is to remove Ni (II) ions from aqueous solutions by adsorption. Activated-carbon prepared from olive stone (ACOS) was used as adsorbent. Different particle size and concentration of ZnCl2 were studied to optimize adsorbent surface area. Initial concentration, temperature, time, and pH were selected as parameters. According to the experiments results, the equilibrium time, optimum pH, and adsorbent dosage were found 60 min, pH > 6, and 1.0 g/50 mL, respectively. In addition, raw olive s...
Removal of disinfection by-product precursors by UF and NF membranes in low-SUVA waters
Ates, Nuray; Yılmaz, Levent; Kitis, Mehmet; Yetiş, Ülkü (Elsevier BV, 2009-2)
The performance of ultrafiltration (UF) and nanofiltration (NF) membranes on disinfection by-products (DBPs) precursor removal in a surface water having low-to-medium dissolved organic carbon (DOC) and specific ultraviolet absorbance (SUVA(254)) levels was evaluated. While higher molecular weight (HMW) DOC fraction was successfully rejected (> 90%), lower molecular weight (LMW) fraction could be removed only 1.5-30% by the tested four different membranes (two UF and two NF). This finding suggested that alth...
Removal of Pesticides from Wastewater by Membrane Proces
Ateş, Nuray; Uzal, Niğmet; Yetiş, Ülkü; Dilek, Filiz Bengü (2021-06-23)
Purpose: The aim of this study was to investigate the removal performances of four pesticides (tributyl phosphate, flutriafol, dicofol and irgarol) by RO membranes. Methods: Three different RO membranes (BW30-LE, SW30-XLE and GE-AD) were used to reject pesticides in two transmembrane pressures of 10 and 20 bar in bench-scale membrane filtration cell. Tributyl phosphate and flutriafol were detected by GC/MS and dicofol and irgarol were monitored by HLPC instruments. Results: While the highest removal of trib...
Isolation of antimicrobial molecules from agricultural biomass and utilization in xylan-based biodegradable films
Çekmez, Umut; Bakır, Ufuk; Department of Biotechnology (2010)
Cotton stalk lignin extractions were performed via alkaline methods at different conditions. Crude and post treated cotton stalk lignins, olive mill wastewater and garlic stalk juice were examined in terms of antimicrobial activity. Antimicrobial lignin was isolated depending on alkaline extraction conditions. Lignin extracted at 60°C exhibited significant antimicrobial effect towards both Escherichia coli and Bacillus pumilus. However different post treatments such as ultrasonication and TiO2-assisted phot...
Removal of hexavalent chromium anions via polymer enhanced ultrafiltration using a fully ionized polyelectrolyte
HAKTANIR, CEREN; Ozbelge, H. Onder; Bicak, Niyazi; Yılmaz, Levent (Informa UK Limited, 2017-01-01)
A fully ionized polyelectrolyte was synthesized for Cr(VI) removal from aqueous solutions by continuous polymer enhanced ultrafiltration (PEUF). Effect of operating parameters such as pH, loading, polymer, and competing ion concentrations were examined. Highest Cr(VI) retention was obtained at a loading of 0.01 at pH 4. Increasing both polymer and chromate concentrations at a fixed loading of 0.01 decreased the retention which demonstrated the effect of crowding. In the presence of competing anions such as ...
Citation Formats
K. Gedik and İ. İmamoğlu, “Removal of cadmium from aqueous solutions using clinoptilolite: Influence of pretreatment and regeneration,” JOURNAL OF HAZARDOUS MATERIALS, pp. 385–392, 2008, Accessed: 00, 2020. [Online]. Available: