Adsorption of heavy metals (Cu 2+ and Zn 2+ ) on novel bifunctional ordered mesoporous silica: Optimization by response surface methodology

In this study, preparation of Eichhornia crassipes stem biochar (ECSBC) was optimized and applied for the removal of Cd2+ from aqueous solution. To obtain the best adsorption capacity of ECSBC, the response surface methodology (RSM) was used to optimize the preparation conditions of ECSBC (OECSBC). The interactions among heating time (X1), heating temperature (X2) and heating rate (X3) were designed by Box-Behnken Design (BBD) experiments. The software gave seventeen runs experiment within the optimal conditions towards two response variables (removal rate and adsorption capacity for Cd2+). The results showed that the mathematical model could fit the experimental data very well and the significance of the influence factors followed the order as heating temperature (X2) > heating rate (X3) > heating time (X1), and the influence of interaction term is: X1 and X2 (heating time and heating temperature) > X2 and X3 (heating temperature and heating rate) > X1 and X3 (heating time and heating rate). Based on the analysis of variance and the method of numerical expected function, the optimal conditions were heating time of 2.42 h, heating temperature of 393 °C, and heating rate of 15.56 °C/min. Under the optimum conditions, the predicted the maximum removal rate and adsorption capacity were 85.2724% and 21.168 mg/g, respectively, and the experimental value of removal rate and adsorption capacity for Cd2+ were 80.70% and 20.175 mg/g, respectively, the deviation from the predicted value were 5.36% and 4.69%. The results confirmed that the RSM can optimize the preparation conditions of ECSBC, and the adsorption capacity of OECSB was improved.

show abstract

“…The removal rate ( R% ) of Cd 2+ and the adsorption capacity ( q t ) were determined using the following Eqs. (2) and (3) 43 , respectively:…”

Section: Methodsmentioning

confidence: 99%

Optimization of biochar preparation from the stem of Eichhornia crassipes using response surface methodology on adsorption of Cd2+

Zhou

Zhang

Zhou

et al. 2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…At the same equilibrium concentrations, the p-nitrophenol adsorption capacity of biochar increased as the temperature of the experiment increased, indicating that the said increase in the experimental temperature was beneficial to the adsorption process. The slope and intercept of the straight line obtained plotting lnK versus 1/T represent the values of ΔH and ΔS of the adsorption reaction (Table 4), respectively 38 . The fact that ΔH is positive and that its value increases as the pyrolysis temperature increases indicates that the adsorption process is endothermic and that p-nitrophenol has more energy when adsorbed onto high-temperature biochar samples than when adsorbed onto low-temperature samples.…”

Section: Factors That Impact P-nitrophenol Adsorption Effect Of Adsomentioning

confidence: 99%

Adsorption characteristics and mechanism of p-nitrophenol by pine sawdust biochar samples produced at different pyrolysis temperatures

Liu

Deng

Shi

2020

Sci Rep

View full text Add to dashboard Cite

Biochar is becoming a low-cost substitute of activated carbon for the removal of multiple contaminants. In this study, five biochar samples derived from pine sawdust were produced at different pyrolysis temperatures (300 °C-700 °C) and used adsorbents to remove p-nitrophenol from water. Results indicate that, as the pyrolysis temperature increases, the surface structure of biochar grows in complexity, biochar's aromaticity and number of functional group decrease, and this material's polarity increases. Biochar's physiochemical characteristics and dosage, as well as solution's pH and environmental temperature significantly influence the p-nitrophenol adsorption behavior of biochar. p-nitrophenol adsorption onto biochar proved to be an endothermic and spontaneous process; furthermore, a greater energy exchange was observed to take place when biochar samples prepared at high temperatures were utilized. the adsorption mechanism includes physical adsorption and chemisorption, whereas its rate is mainly affected by intra-particle diffusion. Notably, in biochar samples prepared at low temperature, adsorption is mainly driven by electrostatic interactions, whereas, in their high-temperature counterparts, p-nitrophenol adsorption is driven also by hydrogen bonding and π-π interactions involving functional groups on the biochar surface.

show abstract

“…where N a is Avogadro' s number. Given the atomic mass of N=14 g mol 1 , AMSM contained 5.76 mmol of amine groups per gram of adsorbent, the surface density of d=5.17 groups per nm 2 of adsorbent surface and intermolecular distance of l=0.43 nm, which confirmed that high degree of amine groups were efficiently attached on the surface and pore of the silica microspheres [32].…”

Section: -5 N 2 Adsorption-desorption Analysismentioning

confidence: 75%

Facile and simple synthesis of triethylenetetramine-modified mesoporous silica adsorbent for removal of Cd(II)

Abedi

Taleghani

Ghorbani

et al. 2018

Korean J. Chem. Eng.

Self Cite

View full text Add to dashboard Cite

Monodispersed porous silica microspheres (SM) were synthesized and further functionalized with amine moieties using triethylenetetramine (TETA) in order to obtain a novel adsorbent for Cd(II) elimination from aqueous media. The morphology, texture and structure of samples were characterized with the aid of Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), energy dispersive spectroscopy (EDS), and N 2 adsorption-desorption. The adsorption efficiency was investigated based on the effect of operational parameters including pH of the solution, the dose of adsorbent, adsorption time, initial concentration of Cd(II) ions and temperature. The equilibrium, kinetics and thermodynamics of Cd(II) adsorption were also studied. The maximum adsorption capacity of amine functionalized silica microspheres (AMSM) for Cd(II) was 35.6 mg g 1 . Cd(II) adsorption onto AMSM had highest consistency with Sips and Langmuir isotherms, while adsorption kinetics was best fitted with pseudo-second order model. Thermodynamics of adsorption revealed that Cd(II) adsorption on AMSM was spontaneous, feasible and exothermic with physical interactions and pore diffusion being the dominant mechanisms in the adsorption process. Results confirmed that AMSM adsorbent has the potential to be a suitable candidate for Cd(II) removal from aqueous solutions.

show abstract

Adsorption of heavy metals (Cu 2+ and Zn 2+ ) on novel bifunctional ordered mesoporous silica: Optimization by response surface methodology

Cited by 74 publications

References 88 publications

Optimization of biochar preparation from the stem of Eichhornia crassipes using response surface methodology on adsorption of Cd2+

Optimization of biochar preparation from the stem of Eichhornia crassipes using response surface methodology on adsorption of Cd2+

Adsorption characteristics and mechanism of p-nitrophenol by pine sawdust biochar samples produced at different pyrolysis temperatures

Facile and simple synthesis of triethylenetetramine-modified mesoporous silica adsorbent for removal of Cd(II)

Contact Info

Product

Resources

About