Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosc...Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosco py （ICP-AES） from aqueous solutions using Ghezeljeh montmorillonite nanoclay as a new natural adsorbent. The Ghezeljeh clay is characterized by using Fourier Transform Infrared （FT-IR） Spectroscopy, Scanning Electron Mi- croscopy-Energy Dispersive Spectrometry （SEM-EDS） and X-ray Diffractometry （XRD） and X-ray Fluorescence （XRF）. The results of XRD and FT-IR of nanoclay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of Ghezeljeh clay, it can be seen that the distance between the plates is Nano. The effects of varying parameters such as initial concentration of metal ions, pH and type of buffer solutions, amount of ad- sorbent, contact time, and temperature on the adsorption process were examined. The effect of various interfer- ing ions was studied. The adsorption data correlated with Freundlich, Langmuir, Dubinin-Radushkevich （D-R）, and Temkin isotherms. The Langmuir and Freundlich isotherms showed the best fit to the equilibrium data for Hg（II）, but the equilibrium nature of Cu（ll） adsorption has been described by the Langmuir isotherm. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models, The adsorp- tion process follows a pseudo-second-order reaction scheme, Calculation of AGσ, △Hσ and ASσ showed that tilenature of Hg（II） ion sorption onto the Ghezeljeh nanoclay was endothermic and was favored at higher temper- attire, and the nature of Cu（II） ion sorption was exothermic and was favored at lower temperature,展开更多
Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） ...Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） have a significant effect on the HM removal by clay mineral sorbents. However, the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown. To resolve this, clay mineral-rich soil column of varying composition, loaded （i） with Cu, Zn and Ni only, （ii） first with DOM followed by Cu, Zn and Ni, or （iii） with DOM, Cu, Zn and Ni simultaneously, was used in a set of desorption experiments. The soil columns were leached with 0.001 mol L-1 CaCI2 dissolved in water as control eluent and 0.001 tool L-1 CaC12 dissolved in DOM as treatment eluent. During the preceding loading phase of the sorbent, the timing of DOM addition （sequential or concurrent with HMs） was found to have a significant influence on the subsequent removal of the HMs. In particular when the column was loaded with DOM and HMs simultaneously, largely irreversible co-precipitation took place. Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM. In contrast, in manured agricultural fields （where HMs enter together with DOM）, HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.展开更多
基金financial support for this work by the Imam Khomeini International University (IKIU)Mines and Mining Industries Development and Renovation Organization of Iran (IMIDRO)
文摘Heavy metal determination was carried out by applying the solid phase extraction （SPE） method in batch mode followed by atomic absorption spectroscopy （AAS） and inductively coupled plasma atomic emission spectrosco py （ICP-AES） from aqueous solutions using Ghezeljeh montmorillonite nanoclay as a new natural adsorbent. The Ghezeljeh clay is characterized by using Fourier Transform Infrared （FT-IR） Spectroscopy, Scanning Electron Mi- croscopy-Energy Dispersive Spectrometry （SEM-EDS） and X-ray Diffractometry （XRD） and X-ray Fluorescence （XRF）. The results of XRD and FT-IR of nanoclay confirm that montmorillonite is the dominant mineral phase. Based on SEM images of Ghezeljeh clay, it can be seen that the distance between the plates is Nano. The effects of varying parameters such as initial concentration of metal ions, pH and type of buffer solutions, amount of ad- sorbent, contact time, and temperature on the adsorption process were examined. The effect of various interfer- ing ions was studied. The adsorption data correlated with Freundlich, Langmuir, Dubinin-Radushkevich （D-R）, and Temkin isotherms. The Langmuir and Freundlich isotherms showed the best fit to the equilibrium data for Hg（II）, but the equilibrium nature of Cu（ll） adsorption has been described by the Langmuir isotherm. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models, The adsorp- tion process follows a pseudo-second-order reaction scheme, Calculation of AGσ, △Hσ and ASσ showed that tilenature of Hg（II） ion sorption onto the Ghezeljeh nanoclay was endothermic and was favored at higher temper- attire, and the nature of Cu（II） ion sorption was exothermic and was favored at lower temperature,
基金supported by a scholarship from the Faculty of Science, University of Amsterdam, The Netherlands
文摘Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals （HMs） Cu, Zn and Ni. The presence and timing of ddition of natural dissolved organic matter （DOM） have a significant effect on the HM removal by clay mineral sorbents. However, the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown. To resolve this, clay mineral-rich soil column of varying composition, loaded （i） with Cu, Zn and Ni only, （ii） first with DOM followed by Cu, Zn and Ni, or （iii） with DOM, Cu, Zn and Ni simultaneously, was used in a set of desorption experiments. The soil columns were leached with 0.001 mol L-1 CaCI2 dissolved in water as control eluent and 0.001 tool L-1 CaC12 dissolved in DOM as treatment eluent. During the preceding loading phase of the sorbent, the timing of DOM addition （sequential or concurrent with HMs） was found to have a significant influence on the subsequent removal of the HMs. In particular when the column was loaded with DOM and HMs simultaneously, largely irreversible co-precipitation took place. Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM. In contrast, in manured agricultural fields （where HMs enter together with DOM）, HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.
