scholarly journals Preparation and characterization of bioadsorbent beads for removing selected heavy metal ions from wastewater

2018 ◽  
Author(s):  
◽  
Suhaib S. Salih

Rapid industrialization is one of the major threats to water pollution worldwide, as discharge effluents contain large amounts of toxic metal ions. Heavy metals are highly toxic to the ecosystem and human even at very low concentrations. We focused on easily available, green and eco-friendly with low operational cost materials to remove heavy metals from industrial wastewater. Chitosan is considered an alternative and sustainable adsorbent due to its highly efficient adsorption capacities for heavy metals. In this particular study, chitosan was successfully modified by using diatomaceous earth and then fabricated as spherical beads using the drop-wise method. Pristine chitosan (CS) beads and chitosan coated diatomaceous earth (CSDE) beads were used to remove zinc, chromium, lead, and nickel ions from aqueous solutions in batch and continuous adsorption processes. The prepared adsorbents were characterized by using scanning electron microscopy (SEM) B Brunauer-Emmett-Teller (BET), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and zeta potential. The results showed that the prepared adsorbents were porous in nature and the total surface area were increased from 1.9 m2/g for pristine chitosan to 14.4 m2/g for chitosan coated diatomaceous earth. The performance of prepared adsorbents was investigated at different temperatures, initial pH of the solution, contact times, initial metal concentrations. The pseudo-second-order kinetic model is more likely to predict the kinetic behavior of the metal ions adsorption process for the whole used contact time range, and the adsorption isotherm data of CS and CSDE beads were well fitted to Langmuir model. The maximal adsorption capacities of prepared CSDE beads were found to be pH dependent as follows: - Zinc ion - 127.4 mg/g at initial Zn(II) concentration 500 mg/L and pH 6. - Chromium ion - 84.23 mg/g at initial Cr(VI) concentration 1000 mg/L and pH 3. - Lead ion - 175.22 mg/g at initial Pb(II) concentration 400 mg/L and pH 7. - Nickel ion - 149.64 mg/g at initial Ni(II) concentration 400 mg/L and pH 6. Successful desorption and regeneration of prepared adsorbents were achieved (with common chemicals) and possessed excellent reusability (up to 10 cycles without a significant loss in adsorption capacity). The common anions and cations coexisting ions have insignificant impact on the removal capacity of prepared adsorbents. Overall, these results suggest that the environmentally friendly materials might be recognized as effective adsorbent and sustainable means for the separation of heavy metals from wastewater streams. That will lead to a new solution to water pollution required in the modern industrial society.

Author(s):  
Zeinab Ezzeddine ◽  
Batoul Solh ◽  
Hussein Hamad

<p>Herein, the removal of heavy metals on thiol modified oak charcoal was investigated. The modified charcoal was characterized by X-ray diffraction, granulometric analysis and infrared spectroscopy. Then, its adsorption efficiency for the removal of Cd2+, Cu2+ and Pb2+ from water was tested. The effects of several conditions on metals adsorption were investigated such as contact time, pH, electrolytes and the initial metal ions concentration. The adsorption capacities were high (197, 250 and 214 mg g-1 for Cd2+, Pb2+ and Cu2+ respectively). The selectivity was also dependent on the metal ions nature and the functional group used. The mechanism of adsorption is complex where several types of interaction between metal ions and the adsorbent surface are involved.</p>


Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 486
Author(s):  
Alcina Johnson Sudagar ◽  
Slávka Andrejkovičová ◽  
Fernando Rocha ◽  
Carla Patinha ◽  
Maria R. Soares ◽  
...  

Metakaolins (MKs) prepared from low-grade kaolins located in the Alvarães (A) and Barqueiros (B) regions of Portugal were used as the aluminosilicate source to compare their effect on the compressive strength and heavy metal adsorption of geopolymers. Natural zeolite, an inexpensive, efficient adsorbent, was used as an additive in formulations to enhance geopolymers’ adsorption capacities and reduce MK utilization’s environmental footprint. Geopolymers were synthesized with the replacement of MK by zeolite up to 75 wt.% (A25, B25—25% MK 75% zeolite; A50, B50—50% MK 50% zeolite; A75, B75—75% MK 25% zeolite; A100, B100—100% MK). The molar ratios of SiO2/Al2O3 and Na2O/Al2O3 were kept at 1 to reduce the sodium silicate and sodium hydroxide environmental impact. Geopolymers’ crystallography was identified using X-ray diffraction analysis. The surface morphology was observed by scanning electron microscopy to understand the effect of zeolite incorporation. Chemical analysis using X-ray fluorescence spectroscopy and energy dispersive X-ray spectroscopy yielded information about the geopolymers’ Si/Al ratio. Compressive strength values of geopolymers obtained after 1, 14, and 28 days of curing indicate high strengths of geopolymers with 100% MK (A100—15.4 MPa; B100—32.46 MPa). Therefore, zeolite did not aid in the improvement of the compressive strength of both MK-based geopolymers. The heavy metal (Cd2+, Cr3+, Cu2+, Pb2+, and Zn2+) adsorption tests exhibit relatively higher adsorption capacities of Barqueiros MK-based geopolymers for all the heavy metals except Cd2+. Moreover, zeolite positively influenced divalent cations’ adsorption on the geopolymers produced from Barqueiros MK as B75 exhibits the highest adsorption capacities, but such an influence is not observed for Alvarães MK-based geopolymers. The general trend of adsorption of the heavy metals of both MK-based geopolymers is Pb2+ > Cd2+ > Cu2+ > Zn2+ > Cr3+ when fitted by the Langmuir isotherm adsorption model. The MK and zeolite characteristics influence geopolymers’ structure, strength, and adsorption capacities.


2013 ◽  
Vol 789 ◽  
pp. 176-179 ◽  
Author(s):  
Eny Kusrini ◽  
Nofrijon Sofyan ◽  
Dwi Marta Nurjaya ◽  
Santoso Santoso ◽  
Dewi Tristantini

Hydroxyapatite/chitosan (HApC) composite has been prepared by precipitation method and used for removal of heavy metals (Cr6+, Zn2+and Cd2+) from aqueous solution. The HAp and 3H7C composite with HAp:chitosan ratio of 3:7 (wt%) were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy-energy dispersive X-ray spectroscopy. The SEM results showed that HAp is spherical-shaped and crystalline, while chitosan has a flat structure. SEM micrograph of 3H7C composite reveals crystalline of HAp uniformly spread over the surface of chitosan. The crystal structure of HAp is maintained in 3H7C composite. Chitosan affects the adsorption capacity of HAp for heavy metal ions; it binds the metal ions as well as HAp. The kinetic data was best described by the pseudo-second order. Surface adsorption and intraparticle diffusion take place in the mechanism of adsorption process. The binding of HAp powder with chitosan made the capability of composite to removal of Cr6+, Zn2+and Cd2+from aqueous solution effective. The order of removal efficiency (Cr6+> Cd2+> Zn2+) was observed.


Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.


2017 ◽  
Vol 18 (4) ◽  
pp. 1406-1419
Author(s):  
F. Elmi ◽  
R. Chenarian Nakhaei ◽  
H. Alinezhad

Abstract This study is the first report of its type demonstrating the synthesis of mHAP on the basis of magnetic functionalization with nHAP, which were synthesized using Rutilus frisii kutum fish scale as a benign fishery waste by-product. The mHAP was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX), and Fourier transform infrared (FT-IR) spectroscopic techniques. The XRD pattern confirmed the formation of a single-phase nHAP without any extra steady phases. It was also found that the pseudo-second-order kinetic model gave a satisfactory fit to the experimental data (R2 = 0.99). The maximum removal percentages of Cu and Zn ions in optimal conditions (adsorbent dosage at 0.1 g, 30 min contact time at 25 ± 1 °C and pH = 5 ± 0.1) by mHAP were 97.1% and 93.8%, respectively. Results also demonstrated that mHAP could be recycled for up to five cycles in the case of copper and zinc. The Langmuir isotherm was proved to have a better correlation compared with that of the Freundlich isotherm. The thermodynamic parameters indicated that it was a spontaneously endothermic reaction. In conclusion, mHAP could be regarded as a powerful candidate for efficient biosorbent, capable of adsorbing heavy metals from aqueous solutions.


2018 ◽  
Vol 51 ◽  
pp. 03004
Author(s):  
Nima Moazezi ◽  
Mohammad Ali Moosavian

In this study, polyaniline modified with cobalt-hexacyanoferrate (PmCH) composite was synthesized and characterized for removal of Rb+, Cd2+, Zn2+, Pb2+, and Ni2+ by FTIR and XRD. The effect of pH, adsorbent dosage, ionic strength, contact time, initial ion concentration, and temperature were studied. The competition adsorption experiments between metal ions were investigated. Batch desorption was also conducted to evaluate the reusability of PmCH. The maximum adsorption capacities were 96.15, 27.17, 17.85, 19.15, and 4.76 mg g-1 of Rb+, Cd2+, Zn2+, Pb2+, and Ni2+, respectively. The optimum pH was determined at natural pH of each solution.


2010 ◽  
Vol 26-28 ◽  
pp. 835-838 ◽  
Author(s):  
Dong Zhang ◽  
Zhi Jiang Liu

Nano-calcium titanate-based coated silica gel G (GCTO) was prepared by the citric acid sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Its lead, cadmium and nickel ions adsorption properties from water were studied. Adsorption and elution were investigated under different conditions. The results showed that the nanometer calcium titanate was immobilized on the silica gel G firmly, becoming a new composite adsorbent. The lead, cadmium and nickel ions were quantitatively retained at pH 5-9; their adsorption capacities of GCTO were 114 mg•g-1, 11.2 mg•g-1 and 20.1 mg•g-1, respectively. The adsorbent can be regenerated completely by elution with 1 mol•L-1 HNO3. The adsorbent has a promising prospect in removal or enriching and separation of heavy metals in water.


Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1209
Author(s):  
Zhe Yang ◽  
Wenyong Hu ◽  
Bin Yao ◽  
Liangchen Shen ◽  
Feifeng Jiang ◽  
...  

A novel manganese-rich pokeweed biochar was prepared at different temperatures from manganese-rich pokeweed plants collected at manganese tailings, resulting in materials identified as BC300, BC400, and BC500. The synthetized biochar materials were investigated as regards their potential for removing Cu2+, Pb2+, and Cd2+, specifically in terms of adsorption performances, adsorption kinetics, adsorption isotherms, and potential environmental pollution risk. The results showed that the sorption process fitted well to the pseudo-second-order kinetic and Langmuir models, and the maximum adsorption capacities of BC500 were 246, 326, and 310 mg·g−1 for Cu2+, Pb2+, and Cd2+ respectively. The physicochemical characteristics of the biochars, and the adsorption mechanisms, were revealed by using scanning electron microscopy-energy spectrometer, elemental analysis, Brunauer–Emmett–Teller techniques, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The sorption mechanism of these three heavy metal ions onto biochars included ion exchange, electrostatic adsorption, chemical adsorption, and precipitation. Besides, the potential pollution risk of manganese-rich pokeweed biochars was significantly reduced after pyrolysis. Therefore, it is feasible to transform manganese-rich pokeweed biomass into manganese-rich pokeweed biochar with potential for heavy metals removal, showing high adsorption capacity, recyclability, and low environmental pollution.


2012 ◽  
Vol 77 (3) ◽  
pp. 393-405 ◽  
Author(s):  
Zavvar Mousavi ◽  
Abdorrahman Hosseinifar ◽  
Vahdat Jahed

Polyacrylamide (PAA), as an adsorbent was investigated for the removal of Ni(II) and Cr(III) metal ions from their synthesized aqueous solutions. The different variables affecting the adsorption capacity of the adsorbent such as contact time, pH of the sorption medium, metal ions concentration and temperature of the solution were investigated on a batch sorption basis. The adsorption equilibrium data fitted best with the Langmuir isotherm model. The maximum adsorption capacities found to be 84.03 and 32.67 mg g-1 of the polyacrylamide for Cr(III) and Ni(II), respectively. Three kinetic models including the pseudo-first-order, pseudo-second-order and intraparticle diffusion equations were selected to follow the adsorption process. Kinetic parameters such as rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was indicated that the adsorption of both ions onto polyacrylamide could be described by the pseudo-second-order kinetic model. Different thermodynamic parameters such as ?H?, ?S? and ?G? have also been evaluated and it has been found that the sorption was feasible, spontaneous and exothermic.


2019 ◽  
Vol 4 (1) ◽  
pp. 42
Author(s):  
Linda Hevira ◽  
Rahmiana Zein ◽  
Edison Munaf

On cause of environmental pollution is the presence of heavy metals. Heavy metal such as Cd (II), Pb (II) and Cu (II) are the metals commonly found in water pollution. The untapped shell of ketapang fruit can be used as an absorbent because it has an active side that can bind to the metal ion. From the research with batch sistem was found that the absorption efficiency of metal Cd (II), Pb (II) and Cu (II) by shell of ketapang will be optimum if done at pH 6 with contact time 60 minute for ion Cd(II), 45 minute for ion Pb (II) and 75 minute for ion Cu. The optimum stirring speed of each is 100 rpm, 150 rpm and 100 rpm. The optimum absorption efficiency occured at concentration of 10 mg/L on metal Cd (II) and Pb (II) that are 86,38 % and 98,51 % while the Cu (II) metal at 5 mg/L concentration is 94,06 % with mass of ketapang 0.1 g,0.5 g and 0.5 g each metal ion. The metal ion concentration was analyzed by AAS and the dominant functional group binding metal ions was analiyzed by FTIR Salah satu penyebab pencemaran lingkungan adalah terdapatnya logam berat. Logam berat seperti Cd, Pb dan Cu merupakan logam yang sering ditemukan dalam pencemaran air. Cangkang buah ketapang yang tidak termanfaatkan dapat dijadikan sebagai penyerap karena mempunyai sisi aktif yang dapat berikatan dengan ion logam. Dari penelitian dengan sistem batch didapatkan bahwa efisiensi penyerapan ion logam Cd (II), Pb (II) dan Cu II) oleh cangkang buah ketapang akan optimum jika dilakukan pada pH 6 dengan waktu kontak 60 menit untuk ion Cd (II), 45 menit untuk ion Pb (II) dan 75 menit untuk ion Cu (II). Kecepatan pengadukan optimum masing-masingnya adalah 100 rpm, 150 rpm dan 100 rpm. Efisiensi penyerapan optimum terjadi pada konsentrasi 10 mg/L pada logam Cd(II) dan Pb (II) yaitu 86,38 % dan 98, 51 %, sedangkan logam Cu (II) terjadi pada konsentrasi 5 mg/L yaitu 94,06 % dengan massa cangkang buah ketapang 0.1 g, 0.5 dan 0.5 g pada masing-masing ion logam. Konsentrasi ion logam dianalisis dengan Spektrofotometri Serapan Atom dan gugus fungsi dominan yang mengikat ion logam dianalisis dengan FTIR.


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