The present research study is focused on green fabrication of superparamagnetic Phytogenic Magnetic Nanoparticles (PMNPs), and then its surface functionalization with 3-Mercaptopropionic acid ...(3-MPA). The resulting material (i.e. 3-MPA@PMNPs) characterized by FTIR, powder XRD, SEM, TEM, EDX, VSM, BET and TGA techniques and then further employed for the investigation of the adsorptive removal of lead (Pb2+) and cadmium (Cd2+) ions from aqueous solutions in single and binary systems. The material showed fastest adsorptive rate (98.23%) for Pb2+ and (96.5%) Cd2+ within the contact time of 60 min at pH 6.5 in the single system. The experimental data were fitted well to Langmuir isotherm, indicated monolayer adsorption of both metal ions onto 3-MPA@PMNPs and an estimated comparable adsorptive capacity of 68.41 mg·g−1 (Pb2+) and 79.8 mg·g−1 (Cd2+) at pH 6.5. However, kinetic data agreed well with pseudo-second-order model, and indicated that the removal mainly supported chemisorption and/ or ion-exchange mechanism. Thermodynamic parameters such as ΔGo, ΔHo, and ΔSo, were −3259.20, 119.35 and 20.73 for Pb2+, and −1491.10, 45.441 and 7.87 for Cd2+ at temperature 298.15 K, confirmed that adsorption was endothermic, spontaneous and favorable. The material demonstrated higher selectivity of Pb2+ and its removal efficiency was (98.20 ± 0.3)% in binary system experiments. The material persisted performance up-to seven (07) consecutive treatment cycles without losing their stability and offered comparable fastest magnetic separation (35 s) from aqueous solutions. Therefore, it is recommended that the prepared material can be employed to remove toxic heavy metal ions from water/wastewaters and this “green” method can easily be implemented at large scale in low economy countries.
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Treatment of toxic and emerging pollutants (T&EPs) is increasing the threats to the survival of conventional wastewater treatment (WWTs) technologies. The high installation and operational costs of ...advanced treatment technologies have shifted the research interest to the development of economical and reliable technology for management of T&EPs. Thus, recently biogenic nanoparticles (BNPs) fabricated using microbes/microorganisms are getting tremendous research interest due to their unique properties (i.e. high specific surface area, desired morphology, catalytic reactivity) for the biodegradation and biosorption of T&EPs. In addition, BNPs can be manufactured using metal contaminated water which indicates a hidden potential for resource recovery and utilization. Therefore, the present study discusses the adsorptive and catalytic performance of BNPs in the removal of T&EPs from water (W) and wastewater (WW). In addition, inspired by the superior performance of BNPs in advance WWT, a model of BNPs based WWT resource recovery and utilization process is also proposed. Finally, main issues i.e. mass production, leaching, poisoning/toxicity, regeneration, reusability and fabrication costs and process optimization are discussed which are main hinders in the transfer of BNPs based WWT technologies from laboratory to commercial scale.
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•Fabrication and applications of biogenic nanoparticles (BNPs) in WWT are discussed.•Adsorptive and catalytic performance of biogenic nanoparticles is critically reviewed.•Pollutants removal mechanism via BNPs is explored and compared.•Functioning of BNPs based WWT technology is discussed for commercial applications.
In this study, a granular adsorbent material containing zero valent iron (ZVI-GAM) was made with fly ash as skeletal material, bentonite as binder and Enteromorpha prolifera as pore former. ...Zero-valent iron was synthesized by direct reduction of iron ore tailings with the coke as reductant at 900°C in the anoxic atmosphere. SEM/EDX, XRD, FTIR and BET analysis were used to characterize ZVI-GAM. SEM image showed that there were many different size pores in ZVI-GAM. XRD analysis indicated the presence of iron in zero-valent state. FTIR analysis revealed that the surface of ZVI-GAM owned the groups responsible for the heavy metals adsorption. The specific surface area of ZVI-GAM was 8.19m2/g. ZVI-GAM was used as reaction and adsorbent material for the removal of Pb(II) and Cr(VI) from aqueous solutions. The factors affecting Pb(II) and Cr(VI) ions removal by ZVI-GAM in a batch model were studied including initial heavy metal concentrations, contact time, adsorbent dosage, pH values and temperature. Maximum removal capacity for Pb(II) and Cr(VI) by ZVI-GAM was found to be 78.13mg/g and 15.70mg/g. ZVI-GAM had the best adsorption and reduction capacity for Cr(VI) and Pb(II) and could reduce Cr(VI) to Cr(III) and Pb(II) to Pb0. Therefore, ZVI-GAM was an effective, low-cost and recyclable material and had great potential to be a promising technique for heavy metal remediation.
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•A new granular adsorbent material-supported zero-valent iron was prepared.•Zero-valent iron was synthesized by the direct reduction of iron ore powder.•Effects of some parameters on Pb(II) and Cr(VI) removal were studied.•The mechanisms of Pb(II) and Cr(VI) removal by ZVI-GAM were probed.
Soil washing is a promising way to remediate arsenic-contaminated soils. Most research has mostly focused on seeking efficient extractants for removing arsenic, but not concerned with any changes in ...soil properties when using this technique. In this study, the removal of arsenic from a heavily contaminated soil employing different washing solutions including H3PO4, NaOH and dithionite in EDTA was conducted. Subsequently, the changes in soil physicochemical properties and phytotoxicity of each washing technique were evaluated. After washing with 2 M H3PO4, 2 M NaOH or 0.1 M dithionite in 0.1 M EDTA, the soil samples’ arsenic content met the clean-up levels stipulated in China’s environmental regulations. H3PO4 washing decreased soil pH, Ca, Mg, Al, Fe, and Mn concentrations but increased TN and TP contents. NaOH washing increased soil pH but decreased soil TOC, TN and TP contents. Dithionite in EDTA washing reduced soil TOC, Ca, Mg, Al, Fe, Mn and TP contents. A drastic color change was observed when the soil sample was washed with H3PO4 or 0.1 M dithionite in 0.1 M EDTA. After adjusting the soil pH to neutral, wheat planted in the soil sample washed by NaOH evidenced the best growth of all three treated soil samples. These results will help with selecting the best washing solution when remediating arsenic-contaminated soils in future engineering applications.
•H3PO4, NaOH and EDTA can effectively remove arsenic from a heavily contaminated soil.•Soil properties were partially changed after washing.•Wheat grew best in NaOH-treated soil sample.
In this work, Fe/Ni nanoparticles were produced through Fe(II) and Ni(II) reduction by NaBH4 and they were stabilized by a kind of prepared granular adsorbent (Fe/Ni@PGA). Fe/Ni@PGA as an ...environment-friendly activator was used to activate persulfate (PS) for the removal of ciprofloxacin from aqueous solution. Fe/Ni@PGA was systematically characterized via Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The effects of PS concentration, initial solution pH, Fe/Ni@PGA dosage, initial ciprofloxacin concentration, reaction temperature, anions, and natural organic matters on the removal of ciprofloxacin by Fe/Ni@PGA/PS were analyzed. The removal efficiency of ciprofloxacin by Fe/Ni@PGA/PS was 93.24% under an initial pH of 3.0, PS concentration of 10 mM, Fe/Ni@PGA dosage of 0.1 g, and reaction temperature of 30 °C. Fe/Ni@PGA could still exhibit high catalytic activity after nine cycles of regeneration. The removal mechanisms for ciprofloxacin by the Fe/Ni@PGA/PS system were proposed. In summary, the Fe/Ni@PGA/PS system could be applied as a promising technology for ciprofloxacin removal.
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The leaves extract of
was used for the synthesis of the innovative phytogenic magnetic nanoparticles (PMNPs) without adding toxic surfactants. The formation, morphology, elemental composition, size, ...thermal stability, structure and magnetic properties of these PMNPs were examined by UV-visible spectrophotometry, FT-IR, XRD, SEM, EDX, TEM, VSM, XPS, BET and TGA. The reactivity of the obtained PMNPs against decolourising toxic dyes, namely, malachite green (MG), crystal violet (CV) and methylene blue (MB), were investigated by UV-vis spectrophotometry. Further, the factors affecting the removal of dyes, including solution pH, adsorbent dosages, initial concentration of dyes, reaction temperature and contact time, were also investigated. The results revealed the decolourisation of 99.12% of MG and 98.23% of CV within 60 min, and 97.52% of MB within 200 min by the PMNPs using dyes concentration of 25 mg/l at pH 6.5 and 298.15 K. The kinetics outcome indicated that the degradation of dyes matched well to the pseudo first-order reaction kinetics model. Furthermore, the probable degradation mechanism of dyes by the PMNPs, including the adsorption of cationic dye molecules onto the negatively charged surface of adsorbent and the oxidation of the Fe° in the solution, were discussed. Thus, the PMNPs can be produced by the bulk and have great potential to be employed for biomedical/environmental remediation.
Magnetotactic bacteria (MTB) are getting much attention in the recent years due to the biomineralization in their magnetosomes (MS). MS are unique organelles that are bio‐mineralized due to MTB. MS ...contains nanosized crystal minerals of magnetite or greigite covered by bilayer lipid membrane, which are originated from cytoplasmic membrane (CM). MS are organized as an ordered chain into the cell which acts as a miniature compass needle. Furthermore, the biodiversity of MTB and their distribution is principally linked with the characteristics and growths of the MS. MTB are often considered as a part of the bacterial biomass from all of the aquatic environments. There have been a lot of genes that control the functions of MTB by accumulating as clusters of genomes such as magnetosomes genomic island (MAI). Therefore, in the present review, the function of the genes and proteins has been highlighted, which are mainly associated with the construction and formation of MS. In addition, the biodiversity, morphology and cell biology of MTB is discussed in greater detail to understand the formation of MS crystals by MTB.
In this paper, a laboratory-scale process which combined electrolysis (EL) and electrodialysis (ED) was developed to treat copper-containing wastewater. The feasibility of such process for copper ...recovery as well as water reuse was determined. Effects of three operating parameters, voltage, initial Cu
2+ concentration and water flux on the recovery of copper and water were investigated and optimized. The results showed that about 82% of copper could be recovered from high concentration wastewater (HCW, >400
mg/L) by EL, at the optimal conditions of voltage 2.5
V/cm and water flux 4
L/h; while 50% of diluted water could be recycled from low concentration wastewater (LCW, <200
mg/L) by ED, at the optimal conditions of voltage 40
V and water flux 4
L/h. However, because of the limitation of energy consumption (EC), LCW for EL and HCW for ED could not be treated effectively, and the effluent water of EL and concentrated water of ED should be further treated before discharged. Therefore, the combination process of EL and ED was developed to realize the recovery of copper and water simultaneously from both HCW and LCW. The results of the EL–ED process showed that almost 99.5% of copper and 100% of water could be recovered, with the energy consumption of EL ≈3
kW
h/kg and ED ≈2
kW
h/m
3. According to SEM and EDX analysis, the purity of recovered copper was as high as 97.9%.
Rice husk-mediated magnetic biochar (RH-MBC) was manufactured in the present study by liquefaction method. It is applied on the anionic and cationic dyes to investigate their dye adsorption capacity ...from aqueous solutions. Characterization of the prepared materials has been conducted by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope, energy-dispersive X-ray, transmission electron microscopy, Brunauer–Emmett–Teller, vibrating sample magnetometer and point of zero charge (PZC) analysis. From the analyses, it is revealed that the manufactured RH-MBC is super-magnetic and more porous with higher surface area compared with its parent materials. After investigating the adsorption data with different adsorption isotherm and kinetic models, the data were best-fitted with Freundlich model and pseudo-second-order model. The present material shows higher adsorption capacity for representative cationic dye CV (80.04 mg/g) rather than the anionic dye EBT (5.09 mg/g). From the FTIR, XRD, PZC and isotherm studies, it is revealed that the dyes adsorption onto the RH-MBC mainly happened due to the presence of the functional groups like C–O, Fe
3
O
4
, –OH, C=C and C–O. It is concluded that the novel functionalized RH-MBC is an approach to use the waste material (rice husk) to use for wastewater treatment and highly efficient for cationic dyes adsorption. Additionally, due to its super-magnetic properties, it is easily separable by using external magnetic field.
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