Combined performance of biochar sorption and magnetic separation processes for treatment of chromium-contained electroplating wastewater

Wang, Shengye; Tang, Yankui; Kun, Li; Mo, Yayuan; Li, Hao-Feng; Gu, Zhan-qi

doi:10.1016/j.biortech.2014.10.007

Cited by 156 publications

(34 citation statements)

References 34 publications

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“…With an increase of the pH value, the form of

HCr O_{4}^{‐}

changes to

Cr O_{4}^{2‐}

and

C r_{2}^{} O_{7}^{2‐}

. In this case,

HCr {italicO}_{4}^{-}

has higher free energy of adsorption (−2.5 to −0.6 kcaL/mol) than that of

Cr O_{4}^{2‐}

and

C r_{2}^{} O_{7}^{2‐}

(−2.1 to −0.3 kcaL/mol) . As a result, the lower pH value was beneficial to the adsorption of Cr(VI) on the surface of the nZVI particles and the following reduction reaction happened based on Equation .…”

Section: Resultsmentioning

confidence: 99%

Efficient preparation of nanoscale zero‐valent iron by high gravity technology for enhanced Cr(VI) removal

Wang

Zhang

et al. 2019

Can J Chem Eng

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Owing to its strong reducibility capacity, nanoscale zero-valent iron (nZVI) can be widely used in the treatment of wastewater. In this study, nZVI particles with an average size of 14 nm were continuously prepared using a rotating packed bed (RPB) reactor with stainless wire mesh packing. The effects of the surfactant type and the rotating speed of the RPB reactor on the particle size of nZVI were investigated. The results indicated that the average particle size could be notably reduced with the proper addition of PVP in the preparation process. Meanwhile, the particle size could be further decreased by increasing the rotating speed of the RPB. Compared to a stirred tank reactor (STR), the RPB reactor had nZVI with a smaller particle size and a much shorter reaction time. The as-prepared nZVI was further employed to remove Cr(VI) in the simulated sewage. The results indicated that lower pH, higher nZVI dosage, and higher temperature were beneficial to the efficient removal of Cr(VI). The removal process of Cr(VI) well conformed to a pseudo-first-order kinetic model. Thermodynamic studies showed that the reduction of Cr(VI) by nZVI was a spontaneous endothermic reaction process with increased entropy. In addition, nZVI prepared in the RPB displayed higher removal efficiency than the counterpart in the STR, and the removal rate was greatly increased by 17.4 times.

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“…With an increase of the pH value, the form of

HCr O_{4}^{‐}

changes to

Cr O_{4}^{2‐}

and

C r_{2}^{} O_{7}^{2‐}

. In this case,

HCr {italicO}_{4}^{-}

has higher free energy of adsorption (−2.5 to −0.6 kcaL/mol) than that of

Cr O_{4}^{2‐}

and

C r_{2}^{} O_{7}^{2‐}

Section: Resultsmentioning

confidence: 99%

Efficient preparation of nanoscale zero‐valent iron by high gravity technology for enhanced Cr(VI) removal

Wang

Zhang

et al. 2019

Can J Chem Eng

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“…Considering that low content of Si in the original biochar (Figure 1), it would be more accurate to state that Si element probably participates in the adsorption by forming CdSiO 3 , as partly supported by XRD analysis (Figure 6A). In particular, the peak at 446 cm −1 could be assigned to the stretching vibrations of Fe-O, testifying the formation of iron oxides [21]. In contrast, the bands of CMB at 2983 cm −1 (-CH stretching), 2513 cm −1 (CO 3 2− ), 1799 cm −1 , 1037 cm −1 (P-O stretching vibrations of PO 4 3− ), 874 cm −1 (Si-O-Si symmetric stretching), and 567 cm −1 (Si-O-Si bending) were all increased slightly after adsorption.…”

Section: Surface Complexationmentioning

confidence: 96%

“…After the magnetization, M-CMB showed ferromagnetic properties with the saturation magnetization (Ms) of 64.96 emu/g ( Figure S1), which was higher than that of pure Fe 3 O 4 materials (Ms = 58.94 emu/g) [21]. Coincidentally, the SEM-EDS results implied that the iron particles might aggregate to the surface of magnetic biochar ( Figure 1B), which was indicated by the FTIR spectra observing the stretching vibrations of Fe-O (around 565 cm −1 ) [31], and further confirmed by XRD pattern implying the formation of Fe 3 O 4 .…”

Section: Biochar Propertiesmentioning

confidence: 98%

“…Likewise, adsorption isotherm experiments were carried out at initial Cd 2+ concentrations in the range of 10-180 mg/L under the temperature of 293, 303 and 313 K, respectively. The magnetic separation of biochar particles from aqueous solution was investigated using a magnetic field of 0.5 T, according to the methods of Wang et al [21].…”

Section: Adsorption Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Adsorption Behavior and Relative Distribution of Cd2+ Adsorption Mechanisms by the Magnetic and Nonmagnetic Biochars Derived from Chicken Manure

Huang

Zhang

et al. 2020

IJERPH

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The present study investigated the adsorption of Cd2+ by nonmagnetic and magnetic biochars (CMB and M-CMB) derived from chicken manure, respectively. The adsorption characteristics were investigated as a function of initial pH, contact time, initial Cd2+ concentration and magnetic separation. Adsorption process of both biochars were better described by Pseudo-second-order kinetic equation and Freundlich isotherm model, which were spontaneous and endothermic in nature. It was found that maximum capacities were 60.69 and 41.07 mg/g obtained at the initial Cd2+ concentration of 180 mg/L for CMB and M-CMB, and the turbidity of adsorption-treated solution was reduced from 244.3 to 11.3 NTU after magnetic separation of 0.5 min. These indicated that M-CMB had lower adsorption capacity of Cd2+ than CMB, though it was successfully separated from the treated solutions. Furthermore, both biochars before and after adsorption were analyzed by SEM-EDS, XRD and FTIR. Adsorption mechanisms mainly included precipitation, ion-exchange, complexation and Cπ-coordination, in which precipitation and ion-exchange dominated the adsorption process by CMB, while in M-CMB, precipitation was always predominant mechanism, followed by ion-exchange. The two other mechanisms of complexation and Cπ-coordination were trivial in both biochars, jointly contributing 7.21% for CMB and 5.05% for M-CMB to total adsorption. The findings deepen our understanding of the mechanisms governing the adsorption process, which are also important for future practical applications in the removal of heavy metals from wastewater by the biochars.

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“…A similar effect of pH on BC adsorbent was also observed. [59,60] This phenomenon could be attributed to surface functional groups of adsorbent and the metal chemistry in the aqueous solution. [7] It is generally accepted that the speciation of Cr(VI) is depended on the solution pH.…”

Section: Effect Of Ph On Cr(vi) Adsorptionmentioning

confidence: 99%

Highly efficient adsorption of Cr(VI) from aqueous solution by Fe³⁺ impregnated biochar

Hong

Tian

Jiang

et al. 2016

Journal of Dispersion Science and Technology

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Biochar (BC) has been widely used as a low-cost adsorbent for the removal of contaminants from water and soil. However, the adsorption ability of BC towards heavy metal oxyanions (e.g. Cr(VI)) is relatively low due to the negatively charged surface of BC.In this study, pristine BC was impregnated with Fe 3+ to improve its Cr(VI) adsorption capability. Fe 3+ -impregnated BC (Fe 3+ -BC) was successfully synthesized by a simple impregnation method and used for the removal of Cr(VI) from aqueous solution. Various factors affecting the adsorption such as impregnation ratio, pH, adsorbent dosage, contact time, temperature, and the presence of humic acid were investigated in detail. Results showed that Fe 3+ -BC had strong adsorption ability to Cr(VI) with a maximum adsorption capacity of 197.80 mg/g, which were not only significantly higher than that of the pristine Journal of Dispersion Science and Technology 2 BC, but also were superior to many previously reported adsorbents. It was favorable for Cr(VI) adsorption under the condition of acidic and high temperature. The adsorption data obeyed Sips and Langmuir isotherms and the kinetic data were well described by the pseudo-first-order kinetic model. The results herein revealed that the Fe 3+ -impregnated BC had a good potential as a highly efficient material for adsorption of Cr(VI) from aqueous solution. GRAPHICAL ABSTRACT

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Combined performance of biochar sorption and magnetic separation processes for treatment of chromium-contained electroplating wastewater

Cited by 156 publications

References 34 publications

Efficient preparation of nanoscale zero‐valent iron by high gravity technology for enhanced Cr(VI) removal

Efficient preparation of nanoscale zero‐valent iron by high gravity technology for enhanced Cr(VI) removal

Adsorption Behavior and Relative Distribution of Cd2+ Adsorption Mechanisms by the Magnetic and Nonmagnetic Biochars Derived from Chicken Manure

Highly efficient adsorption of Cr(VI) from aqueous solution by Fe³⁺ impregnated biochar

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Combined performance of biochar sorption and magnetic separation processes for treatment of chromium-contained electroplating wastewater

Cited by 156 publications

References 34 publications

Efficient preparation of nanoscale zero‐valent iron by high gravity technology for enhanced Cr(VI) removal

Efficient preparation of nanoscale zero‐valent iron by high gravity technology for enhanced Cr(VI) removal

Adsorption Behavior and Relative Distribution of Cd2+ Adsorption Mechanisms by the Magnetic and Nonmagnetic Biochars Derived from Chicken Manure

Highly efficient adsorption of Cr(VI) from aqueous solution by Fe3+ impregnated biochar

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Highly efficient adsorption of Cr(VI) from aqueous solution by Fe³⁺ impregnated biochar