Metakaolin based geopolymer as an effective adsorbent for adsorption of zinc(II) and nickel(II) ions from aqueous solutions

Kara, İlknur; Yılmazer, Dilek; Akar, Sibel Tunali

doi:10.1016/j.clay.2017.01.008

Cited by 171 publications

(71 citation statements)

References 47 publications

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“…In the era of industrialization contamination of water bodies by heavy metals have become an alarming threat for the mankind and aquatic flora and fauna [1]. The metals which are 6 times heavier than water are identified as heavy metals [2]. Among all, Zn 2+ is one of the most commonly found heavy metal ions.…”

Section: Introductionmentioning

confidence: 99%

Process Optimization Study of Zn2+ Adsorption on Biochar-Alginate Composite Adsorbent by Response Surface Methodology (RSM)

Biswas

Bal

Behera

et al. 2019

Water

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A novel biochar alginate composite adsorbent was synthesized and applied for removal of Zn2+ ions from aqueous solution. Kinetics, equilibrium and thermodynamic studies showed the suitability of the adsorbent. From a Langmuir isotherm study, the maximum monolayer adsorption capacity of the composite adsorbent was found to be 120 mg/g. To investigate the effect of process variables like initial Zn2+ concentration (25–100 mg/L), adsorbent dose (0.4–8 g/L) and temperature (298–318 K) on Zn2+ adsorption, response surface methodology (RSM) based on a three independent variables central composite design of experiments was employed. A quadratic model equation was developed to predict the relationship between the independent variables and response for maximum Zn2+ removal. The optimization study reveals that the initial Zn2+ concentration and adsorbent dose were the most effective parameters for removal of Zn2+ due to higher magnitude of F-statistic value which effects to a large extent of Zn2+ removal. The optimum physicochemical condition for maximum removal of Zn2+ was determined from the RSM study. The optimum conditions are 43.18 mg/L initial metal ion concentration, 0.062 g adsorbent dose and a system temperature of 313.5 K. At this particular condition, the removal efficiency of Zn2+ was obtained as 85%.

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Section: Introductionmentioning

confidence: 99%

Process Optimization Study of Zn2+ Adsorption on Biochar-Alginate Composite Adsorbent by Response Surface Methodology (RSM)

Biswas

Bal

Behera

et al. 2019

Water

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“…This protonated adsorbent surface at pH< 5 is responsible for electrostatic repulsion between MCM‐41 surface and the cationic metal ion resulting no removal . Also, higher concentration of H + in highly acidic pH, and competitive adsorption between H + and metal ions, MCM‐41 shows higher affinity towards H + to adsorb causing protonation of active sites, and thus decreasing the available adsorption sites for metal ions ,. Hence, the adsorption capability of MCM‐41 for Zn (II) was found lower at lower pH.…”

Section: Resultsmentioning

confidence: 99%

“…[44] Also, higher concentration of H + in highly acidic pH, and competitive adsorption between H + and metal ions, MCM-41 shows higher affinity towards H + to adsorb causing protonation of active sites, and thus decreasing the available adsorption sites for metal ions. [13,37] Hence, the adsorption capability of MCM-41 for Zn (II) was found lower at lower pH. As initial pH of the solution is increased, the positively charged active sites on MCM-41are reduced and the negatively charged active sites are increased (equation 2 and 3) which favored the cationic Zn (II) ions adsorption due to electrostatic attraction.…”

Section: Adsorption Of Zn(ii) Onto Mcm-41mentioning

confidence: 99%

Single and Binary Adsorption of Zn (II) and Cr (VI) Heavy Metals onto Synthesized Silica ‐Based MCM‐41

2019

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Effluents from numerous Industries like textile, paint, pharmaceutical, steel and electroplating industries liberate both Zinc [Zn (II)] and Chromium [Cr (VI)] heavy metals. In this work, adsorptive interaction of toxic Zn (II) heavy metal in aqueous solution with synthesized mesoporous silica based MCM‐41 was investigated. Further, the effects of presence of Cr (VI) heavy metal on the adsorption of Zn (II) and vice versa were investigated by simultaneous competitive binary adsorption from Cr (VI) and Zn (II) aqueous binary solution. Batch experiments were executed to see the effects of parameters like pH, adsorbent dose (m), adsorbate concentration and adsorption time (t). Optimum conditions for Zn (II) treatment were obtained as: initial pH (pHi) =7, m=0.1 g/L and t=2 h. Competitive adsorption of both Cr (VI) and Zn (II) from their binary solution was studied at 288− 308 K temperatures. Obtained equilibrium data were then fitted to different competitive multicomponent isotherm models like Langmuir (extended), Freundlich isotherm (extended), Sheindrof‐Rebuhn‐Sheintuch (SRS) isotherm and Redlich‐Peterson isotherm (modified) models, and various isotherm interaction parameters were calculated.

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“…Geopolymers are eco‐friendly aluminosilicates with amorphous to semi‐crystalline structures. The mechanisms of immobilization are both physical and chemical, due to their dense microstructures and chemical sorption capacities . The amorphous or semi‐crystalline structures of geopolymers may even be developed to more stable crystal structures by high‐temperature sintering or hydrothermal synthesis, which would improve the immobilization of radioactive waste elements such as Sr or Cs.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanisms of immobilization are both physical and chemical, due to their dense microstructures and chemical sorption capacities. 12,13 The amorphous or semi-crystalline structures of geopolymers may even be developed to more stable crystal structures by high-temperature sintering or hydrothermal synthesis, 14,15 which would improve the immobilization of radioactive waste elements such as Sr or Cs. On the other hand, a sintering process for geopolymer radioactive waste forms may be regarded as an alternative process for improving the immobilization of a highly alkaline, sodium bearing waste containing large amounts of long-lived radioactive nuclides ( 137 Cs and 90 Sr) and salts.…”

Section: Introductionmentioning

confidence: 99%

Sintering of metakaolin‐based Na/Ca‐geopolymers and their immobilization of Cs

et al. 2019

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Metakaolin‐based Na/Ca‐geopolymers with a designed composition close to feldspar were used as precursors of Cs immobilization form materials. The sintering behaviors of geopolymers and their sintered materials' immobilization of Cs ions were investigated; the results indicated that the major phases of sintered geopolymers are plagioclase feldspars and feldspathoid. With the addition of Cs to the geopolymers, Cs‐leucite phase and caesium silicates were formed at 1150°C and 1170°C, respectively. It was found that Cs addition can slightly decrease the sintering temperature of geopolymers and make the grains finer. In addition, in order to reduce the volatilization of Cs ions during sintering, sintering temperatures of Cs‐geopolymer were further decreased to 850°C by introducing B2O3. After the geopolymer and Cs‐geopolymer were sintered using a low‐temperature liquid‐phase process, they remained structurally plagioclase feldspars and feldspathoid. Leaching on Product Consistency Test indicates that the leaching concentrations of Cs‐geopolymer samples sintered at higher temperatures are lower than those of samples sintered at lower temperatures. Thus, the increased volatilization of Cs ions at the higher temperatures and the formation of Cs‐leucite phase and caesium silicates can lead to the decrease of leaching concentrations in leachates. Therefore, low sintering temperatures and the fabrication of Cs crystalline ceramics are the key factors toward improving the immobilization of Cs ions.

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Metakaolin based geopolymer as an effective adsorbent for adsorption of zinc(II) and nickel(II) ions from aqueous solutions

Cited by 171 publications

References 47 publications

Process Optimization Study of Zn2+ Adsorption on Biochar-Alginate Composite Adsorbent by Response Surface Methodology (RSM)

Process Optimization Study of Zn2+ Adsorption on Biochar-Alginate Composite Adsorbent by Response Surface Methodology (RSM)

Single and Binary Adsorption of Zn (II) and Cr (VI) Heavy Metals onto Synthesized Silica ‐Based MCM‐41

Sintering of metakaolin‐based Na/Ca‐geopolymers and their immobilization of Cs

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