Removal Efficiency Of Heavy Metal Ions Research Articles

Modification of electrospun polyacrylonitrile nanofiber membranes with curcumin quantum dots for enhanced self-cleaning, antifouling and photocatalytic performance for water treatment

This work presents the fabrication of electrospun PAN-CMQD nanofiber membranes by blending laser ablated curcumin quantum dots (CMQD) with polyacrylonitrile (PAN) for water treatment application. The electrospinning process conditions were optimized using TOPSIS-Taguchi L9 (33) approach to develop membranes with superior membrane performance. The PAN-CMQD nanofiber membranes were of average fibre diameter 85.89 nm and exhibited increased hydrophilicity and improved membrane performance with 53.01 %, 36.74 %, 58.03 %, 37.68 % and 57.33 % increase in porosity, solute rejection, fouling rejection ratio, tensile strength and pure water flux respectively in contrast to the pristine PAN membrane. The PAN-CMQD nanofiber membrane possessed enhanced recyclability, self-cleaning ability, antibacterial activity and also showed good heavy metal ion removal efficiency towards Pb2+, Fe2+, Cr6+, Cd2+ and Mn2+. The PAN-CMQD membrane also showed 98.80 % photocatalytic degradation efficiency towards methylene blue dye under visible light irradiation. This study proves that PAN-CMQD nanofiber membrane is efficient in treating contaminated water with improved photocatalytic and self-regeneration capacity and the developed membrane could possibly be deployed for the mitigation of heavy metals and dyes from industrial waste water.

Thiol Functionalized Aloe Vera Fibre Filter: A Simple Portable Water Filter For Heavy Metal Ion Removal

AbstractA novel high efficient filtration system for heavy metal ion adsorption from water bodies has been developed. It is a cost‐efficient filtration system that removes Pb2+ and Cd2+ ions effectively in an efficient manner. Aloe vera fibre that has been alkali‐treated and given a thiol functional is stuffed into a porous tube with a packing density of 0.2, and the porous tube is covered with polyacrylonitrile nanofibre. Functionalized aloe vera fibre and PAN nano fibres were characterized by various techniques such as X‐ray difractiomatry (XRD), Attenuated total reflection‐fourier transforms infrared spectroscopy (ATR‐FTIR), thermo gravimetric analysis (TGA), tensile tester and scanning electron microscopy (SEM). Furthermore, the heavy metal ion removal efficiency of filtration system was examined by inductively coupled plasma‐optical emission spectrometry (ICP‐OES). Inductively coupled plasma‐optical emission spectrometry (ICP‐OES) was used to evaluate the effectiveness of the filtering system‘s ability to remove heavy metal ions. In order to conduct column adsorption tests, the initial metal ion concentration was varied. The breakthrough curves of the trials were then analysed. With the aid of Thomas adsorption isotherm and Yoon‐Nelson model, the adsorption mechanism of thiol functionalized aloe vera fibre was thoroughly investigated. The portable filter has the ability to continuously treat waste water, which is a useful function.

Simultaneous removal of ternary heavy metal ions by a newly isolated Microbacterium paraoxydans strain VSVM IIT(BHU) from coal washery effluent.

In the present work, the removal of Cr (VI), Cd (II) and Pb (II) at 50mg/L of each metal ion concentration was investigated by Microbacterium paraoxydans strain VSVM IIT(BHU). The heavy metal binding on the bacterial cell surface was confirmed through X-ray photoelectron spectroscopy and energy dispersive X-ray. X-ray photoelectron spectroscopy analysis also confirmed the reduction of Cr (VI) to Cr (III). Heavy metal removal dynamics was investigated by evaluating dimensionless, and the value of Nk (9.49 × 10-3, 9.92 × 10-3 and 1.23 × 10-2 for Cr (VI), Cd (II) and Pb (II) ions) indicated that the removal of heavy metals by bacterial isolate was mixed diffusion and transfer controlled. It was found that both the experimental and predicted values for isolated bacterial strain coincided with each other with a good R2 value in the L-M Algorithm range of 0.94-0.98 for the ternary metal ion system. The bacterial isolate presented a maximum heavy metal ion removal efficiency of 91.62% Cr (VI), 89.29% Pb (II), and 83.29% Cd (II) at 50mg/L.

Boosting adsorption of heavy metal ions in wastewater through solar-driven interfacial evaporation of chemically-treated carbonized wood

Once the adsorbent is selected, almost introducing larger specific surface area and more surface functional groups becomes the only way to improve its adsorption performance. However, this approach is generally limited in practical application for intricate and costly engineering steps. Herein, we provided a novel avenue for boosting adsorption activities towards specific metal ions in wastewater. Solar-driven interfacial water evaporation produces the localized temperature field and concentration gradient of metal ions inside small pores, endowing with a new sorption mechanism. By using chemically-treated carbonized wood as all-in-one solar absorption and metal ion adsorption system, we achieved higher water evaporation rate and heavy metal ion removal efficiency than carbonization-only wood reported previously. In particular, this system exhibited a strong dependence of specific metal ion adsorption capacity on solar intensity. Pb2+ adsorption capacity was enhanced by over 225% with the solar intensity increased to 3.0 kW·m−2. This could originate from the formed temperature field localized specially on the surface of adsorbents that not only induces Pb2+ concentration gradient near to solid-liquid interface but also activate inactive adsorption sites. Besides, the chemical-treated & carbonized wood showed excellent cyclic stability and can be directly utilized for wastewater treatment, recovery and reuse.

In-situ enhanced heavy metal ion removal efficiency based on branched amino groups in the forward osmosis process

In-situ enhanced heavy metal ion removal efficiency based on branched amino groups in the forward osmosis process

Effects of operating parameters and coexisting ions on the efficiency of heavy metal ions removal by nano-fibrous metal-organic framework membrane filtration process

The purification process of wastewater containing heavy metal ions (HMIs) using nano-fibrous metal-organic frameworks, MOF-808, embedded polyacrylonitrile membrane has been studied. The process parameters that were evaluated included feed concentration, transmembrane pressure (TMP), and membrane thickness. The effect of coexisting cations in the solution upon the removal efficiencies of Zn2+, Cd2+, Pb2+ and Hg2+ ions was also investigated. Results from the filtration experiments indicate a substantial variation in the feed volume that the membrane can treat before the permeate lead concentration reaches the allowable limit of 10 ppb, depending on the process parameter. An increase in the membrane thickness showed a significant improvement (26%) with 440 L of the treated feed volume after doubling the membrane layer. An increase in TMP could reduce the treated feed volume by 38% while a decrease in feed concentration led to a 21% increase in the treated feed volume. In the presence of other common background cations in the solution, the removal efficiency of HMIs by adsorption onto MOF-808 dropped by 18 to 37%. This result was dependent upon the HMIs, in the presence of up to three other cations but was minimal in the presence of a single cation indicative of good selectivity.

The stability of the compounds formed in the process of removal Pb(II), Cu(II) and Cd(II) by steelmaking slag in an acidic aqueous solution

The potential feasibility of steel slag as a low cost removal agent for heavy metal ions Pb(II), Cu(II) and Cd(II) in acidic conditions was investigated in this study. The initial pH effect on heavy metal ion removal efficiency, the compounds formed after heavy metal ion removal, and the binding force of metals with the compounds were determined. The results showed that the efficiency of removing heavy metal ions by steel slag was low at low initial pH levels, yet it sharply increased and then became stable as the initial pH increased. The pseudo-second order model provided the best description for the removal of Pb, Cu, and Cd ions, indicating that the predominant heavy metal ion removal mechanism was chemisorption. The images obtained by the Fourier transform infrared spectroscopy (FTIR) and the X-ray diffraction (XRD) analysis indicated that the main compounds formed after the removal of Pb, Cu, and Cd ions by steel slag in an aqueous solution were heavy metal ferrites, silicates, carbonates, hydroxides and oxides. Sequential extraction experiments showed that these three heavy metals bond to the compounds mainly in the carbonate fraction (F2), the Fe oxide bound fractions (F3 (a) and F3 (c)), and the residual fraction (F4) in which F2 corresponded to the carbonates, and F3(a), F3(c) and F4 corresponded to the amorphous or crystalline ferrites and silicates, respectively. The F3 (a), F3 (c) and F4 are relatively stable and do not tend to re-release metal ions in acidic solutions. However, F2 and heavy metal hydroxides have relatively low stability and dissolve readily, re-leaching heavy metal ions into the acid solution. When these three heavy metal ion mixtures were removed by steel slag, the Pb, Cu and Cd deposits were at higher levels in the F3 and F4 fractions. Therefore, it was concluded that the co-existence of heavy metal ions in an aqueous solution is beneficial for their removal by steel slag in acidic conditions.

Conversion of municipal solid waste incineration bottom ash to sorbent material: Effect of ash particle size

Conversion of municipal solid waste incineration bottom ash (IBA) to sorbent material can provide an alternative route for the re-utilization of IBA and improve the sustainability of waste incineration technology. Alkaline hydrothermal treatment was adopted in this study for IBA conversion with an emphasis on the effect of IBA particle size. The converted product was determined to contain sodium aluminum silicon phosphorus oxide hydrate (Na13Al24Si13P11O96(H2O)16), katoite (Ca3Al2(SiO4)(OH)8), and other unconverted materials. It is found that IBA of small particle size contains low Si content and promotes the conversion reaction. The presence of high surface area in small particles also facilitates the contact with reagent solution and favors conversion. A reduction in particle size and an increase in surface area were found after hydrothermal conversion. The converted product was adopted as sorbent material and demonstrated promising performance for pollutants (organic dye and heavy metal ions) removal from water. An increase in the surface area of the converted product favored dye adsorption, while an increase in exchangeable cations was found to improve the heavy metal ion removal efficiency. Sorbent converted from IBA in the size range of 0.212–0.6mm was found to show the highest dye removal efficiency, while sorbent obtained from IBA having particle size < 0.212mm performed the best for heavy metal ions adsorption. The adsorption of pollutants was also investigated by isotherm study. The adsorption process was found to follow Langmuir model, indicating that the process was dominated by chemisorption.

An intelligent displacement pumping film system: A new concept for enhancing heavy metal ion removal efficiency from liquid waste

A concept of electrochemically switched ion exchange (ESIX) hybrid film system with piston-like proton pumping effect for the removal of heavy metal ions was proposed. Based on this concept, a novel ESIX hybrid film composed of layered alpha zirconium phosphate (α-Zr(HPO4)2; α-ZrP) nanosheets intercalated with a potential-responsive conducting polyaniline (PANI) was developed for the removal of Ni2+ ions from wastewater. It is expected that the space between α-ZrP nanosheets acts as the reservoir for the functional ions while the intercalated PANI works as the potential-sensitive function element for piston-like proton pumping in such ESIX hybrid films. The prepared ESIX hybrid film showed an excellent property of rapid removal of Ni2+ ions from wastewater with a high selectivity. The used film was simply regenerated by only altering the applied potential. The ion pumping effect for the ESIX of Ni2+ ions using this kind of film was proved via XPS analysis. The proposed ESIX hybrid film should have high potential for the removal of Ni2+ ions and/or other heavy metal ions from wastewater in various industrial processes.