scholarly journals Exploring the Iron Oxide Functionalized Biobased Carbon-silica-polyethyleneimine Composites for Hexavalent Chromium Removal from Dilute Aqueous Solutions

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3081
Author(s):  
Mpho Cynthia Qhubu ◽  
Philiswa Nosizo Nomngongo ◽  
Vusumzi Emmanuel Pakade
Keyword(s):  
Iron Oxide ◽  
Aqueous Solutions ◽  
Hexavalent Chromium ◽  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Spectral Bands ◽  
Pseudo Second Order ◽  
Dilute Aqueous Solutions ◽  
Co Precipitation

The contamination of water resources by toxic hexavalent chromium remains a challenge. In this study, amino-functionalized iron oxide biobased carbon-silica composites were prepared through co-precipitation of Fe(II) and Fe(III) over Macadamia activated carbon and explored as feasible adsorbents for the removal of Cr(VI) from dilute aqueous solutions. The energy dispersive spectroscopy (EDS) elemental analysis confirmed the existence of Fe, Si, O, and C atoms, which form the backbone of the composite. The FTIR also showed the presence of Fe-O and Si-O-Si and Si-OH spectral bands, affirming the backbone of the adsorbents. Cr(VI) adsorption efficiency (5.76 mg/g) was achieved at pH 1 when an initial concentration of 2.5 mg/L, contact time of 90 min, and dosage concentration of 1.7 g/L were used. The data were best described by the Langmuir adsorption model and pseudo-second-order rate model. ΔG° (−3 to −12 kJ/mol) and ΔH° (46, 12 and 5 kJ/mol) values affirmed that the adsorption of Cr(VI) was spontaneous and endothermic and dominated by chemical interactions.

Solvothermal Synthesis of Humic Acid-Supported CeO2 Nanosheets Composite as High Performance Adsorbent for Congo Red Removal

2020 ◽  
Vol 20 (5) ◽  
pp. 3225-3230
Author(s):  
Qiang Ling ◽  
Junsheng Wei ◽  
Ling-Yu Chen ◽  
Hui-Juan Zhao ◽  
Zhao Lei ◽  
...  
Keyword(s):  
Congo Red ◽  
High Performance ◽  
Solvothermal Method ◽  
Mesoporous Structure ◽  
Adsorptive Capacity ◽  
Adsorption Model ◽  
Adsorption Ability ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Pseudo Second Order

Surface properties and structures of materials are essential for their adsorption of pollutants in water. Humic acids (HA)-supported CeO2 nanosheet composites are synthesised by solvothermal method. The size of CeO2 nanosheets are approximately 100–500 nm. The obtained composite exhibits superior adsorption ability for Congo Red (CR) in water, which can be attributed to its unique structure and highly dispersed CeO2 nanosheet. The composite’s adsorption behaviour of CR follows a pseudo-second-order mode and Langmuir adsorption model well, and the maximum adsorptive capacity for CR achieves 260 mg g−1. The presence of CeO2 nanosheets enhances surface area and enriches the mesoporous structure of the composites, thereby promoting CR adsorption capacity.

Removal of chromium from aqueous solutions using modified lettuce leaves

2014 ◽  
Vol 69 (12) ◽  
pp. 2497-2503 ◽  
Author(s):  
Chen Li ◽  
Yan Fen-xia ◽  
Yang Shuai ◽  
Chai Shu-li ◽  
Ma Pei-qin
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
New Materials ◽  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Secondary Pollution ◽  
Synthesis Routes ◽  
Influence Of Ph

This article reports on an investigation into the ability of modified lettuce leaves to extract chromium ions from aqueous solutions. These exciting new materials were prepared via rapid (5 h) environmentally friendly synthesis routes avoiding any secondary pollution. The influence of pH, metal concentration, the adsorption of the added amount, and water temperature on the selectivity and sensitivity of the removal process was investigated. The maximum theoretical adsorption rate of modified lettuce leaves, evaluated by the Langmuir adsorption model, was 99.98%. The proposed method was applied in the determination of Cr6+ in a sample of aqueous solution and was validated by comparison with activated carbon.

Adsorption of Ni2+ and Cu2+ from Aqueous Solution by Polyethylenimine Impregnation of Metal–Organic Frameworks

NANO ◽  
2020 ◽  
Vol 15 (03) ◽  
pp. 2050029 ◽  
Author(s):  
Dan Wang ◽  
Xinfeng Xiao ◽  
Bo Han ◽  
Weiming Ni ◽  
Yu Gao ◽  
...  
Keyword(s):  
Order Kinetic ◽  
Adsorption Model ◽  
Elution Time ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Adsorption Capacities ◽  
Order Kinetic Model ◽  
Metal Organic ◽  
Pseudo Second Order

A series of UiO-66-PEI materials were obtained by impregnating UiO-66 with different amounts of polyethylenimine (PEI) with UiO-66 as the basic skeleton material. The materials were used as adsorbents to remove Ni[Formula: see text] and Cu[Formula: see text] from water. The prepared UiO-66-PEI-30 had good adsorption capacity on Ni[Formula: see text] and Cu[Formula: see text] at 30% PEI. The adsorption of Ni[Formula: see text] and Cu[Formula: see text] with UiO-66-PEI-30 was further studied. The role of eluent types, elution time, concentration and volume on the effect of Cu[Formula: see text] elution was investigated. The adsorption of Ni[Formula: see text] and Cu[Formula: see text] by UiO-66-PEI-30 followed the pseudo-second-order kinetic model and Langmuir adsorption model. The maximum adsorption capacities obtained by Langmuir fitting for Ni[Formula: see text] and Cu[Formula: see text] were 11.54[Formula: see text]mg[Formula: see text]g[Formula: see text] and 24.87[Formula: see text]mg[Formula: see text]g[Formula: see text], respectively. After four desorption/adsorption experiments, UiO-66-PEI-30 still showed good adsorption performance. UiO-66 impregnated with PEI was an adsorbent with adsorption potential.

scholarly journals Determination of the absolute CH4 adsorption using simplified local density theory and comparison with the modified Langmuir adsorption model

RSC Advances ◽  
2018 ◽  
Vol 8 (72) ◽  
pp. 41509-41516
Author(s):  
Yeyu Zhang ◽  
Shaonan Zhang ◽  
Zhicheng Wang ◽  
Hucheng Deng ◽  
Minghui Qi ◽  
...  
Keyword(s):  
Shale Gas ◽  
Local Density ◽  
Gas Storage ◽  
Adsorption Model ◽  
Gas Reservoirs ◽  
Methane Recovery ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Ch4 Adsorption

Accurately determining the adsorbed amount of CH4 on shale is significant for understanding the mechanisms of shale gas storage and shale methane recovery from shale gas reservoirs.

scholarly journals Sodium hydroxide modified rice husk for enhanced removal of copper ions

2018 ◽  
Vol 78 (7) ◽  
pp. 1615-1623 ◽  
Author(s):  
N. Priyantha ◽  
H. K. W. Sandamali ◽  
T. P. K. Kulasooriya
Keyword(s):  
Heavy Metal ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Copper Ions ◽  
Maximum Adsorption Capacity ◽  
Adsorption Model ◽  
Natural Form ◽  
Langmuir Adsorption ◽  
Pseudo Second Order ◽  
Heavy Metal Adsorbent

Abstract Although rice husk (RH) is a readily available, natural, heavy metal adsorbent, adsorption capacity in its natural form is insufficient for certain heavy metal ions. In this context, the study is based on enhancement of the adsorption capacity of RH for Cu(II). NaOH modified rice husk (SRH) shows higher extent of removal for Cu(II) ions than that of heated rice husk (HRH) and HNO3 modified rice husk (NRH). The extent of removal of SRH is increased with the concentration of NaOH, and the optimum NaOH concentration is 0.2 mol dm−3, used to modify rice husk for further studies. The surface area of SRH is 215 m2 g−1, which is twice as much as that of HRH according to previous studies. The sorption of Cu(II) on SRH obeys the Langmuir adsorption model, leading to the maximum adsorption capacity of 1.19 × 104 mg kg−1. Kinetics studies show that the interaction of Cu(II) with SRH obeys pseudo second order kinetics. The X-ray fluorescence spectroscopy confirms the adsorption of Cu(II) on SRH, while desorption studies confirm that Cu(II) adsorbed on SRH does not leach it back to water under normal conditions.

Investigation of Ultrasonic Effects in Cotton Dyeing Processing

2013 ◽  
Vol 787 ◽  
pp. 138-142 ◽  
Author(s):  
De Shuai Sun ◽  
Long Fang ◽  
Tao Liu
Keyword(s):  
Cotton Fiber ◽  
Ultrasound Irradiation ◽  
Cotton Fabrics ◽  
Dye Uptake ◽  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Dyeing Process ◽  
Direct Dye ◽  
Ultrasound Dyeing

Ultrasound can promote the dye-uptake in the dyeing process. The effects of ultrasound on the fiber, dye and dyeing system were investigated by dyeing cotton fabrics with a direct dye. The dye exhaustion exceeded 80% in 30 minutes with the assistant of ultrasound. Langmuir adsorption model could descript the ultrasound dyeing process of direct dye. The area of fiber accessibility of cotton fiber increased 1.68 times under the action of ultrasound. The absorbance of direct dye solution increased remarkably in the first 10 minutes of ultrasound irradiation. Ultrasound accelerated the diffusion of dye on cotton fiber, and then the diffusion coefficient increased 46 times

Evaluation of Chitosan Modified by Sodium Dodecyl Sulfate for Removing Hexavalent Chromium from Aqueous Solutions

2020 ◽  
pp. 13-22
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Aqueous Solutions ◽  
Hexavalent Chromium ◽  
Sodium Dodecyl ◽  
Second Order ◽  
Order Kinetic ◽  
Batch Mode ◽  
Dodecyl Sulfate ◽  
Pseudo Second Order ◽  
Langmuir And Freundlich Models

Hexavalent chromium (Cr(VI)) has the characteristic of forming anionic species, which are very toxic, very soluble in water and difficult to be removed. In this study, dichromate removal from aqueous solutions by chitosan and chitosan modified by sodium dodecyl sulfate (SDS) was addressed. The effect of various experimental parameters, such as pH (1-9), initial concentration (10-100 mg L-1), adsorbent dose (0.005-0.350 g) and contact time (5-60 min) was investigated. All experiments were conducted in batch mode at room temperature (~21 oC). The obtained equilibrium adsorption isotherms were analyzed using the Langmuir and Freundlich models. Furthermore, the kinetics of dichromate removal was analyzed by pseudo-first order, pseudo-second order and the Elovich models. Optimum conditions for obtaining high removal (~97%) within a relatively short time (60 min) are: 5.0 pH, 0.100 g SDS-chitosan dosage and an initial Cr2O72- concentration of 10 mg L-1. The dichromate adsorption capacity of chitosan is 8.3 mg L-1, while that of SDS-chitosan is 9.7 mg L-1. In addition, the adsorption of dichromate by chitosan and SDS-chitosan is well-fitted by the Langmuir and Freundlich models while the adsorption kinetics is best fitted by the pseudo-second-order kinetic model.

scholarly journals A three-site Langmuir adsorption model to elucidate the temperature, pressure, and support dependence of the hydrogen coverage on supported Pt particles

2007 ◽  
Vol 245 (2) ◽  
pp. 415-427 ◽  
Author(s):  
Y JI ◽  
V KOOT ◽  
A VANDEREERDEN ◽  
B WECKHUYSEN ◽  
D KONINGSBERGER ◽  
...  
Keyword(s):  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model

scholarly journals Aizoon Extract As a Novel Eco-friendly Corrosion Inhibitor For Stainless Steel430 in HCl Solution

2021 ◽  
Author(s):  
Ahmed F. Molouk ◽  
Mohamed F. Atia ◽  
Abd El-Aziz S. Fouda
Keyword(s):  
Mixed Type ◽  
Electrochemical Impedance ◽  
Theoretical Data ◽  
Cathodic Reaction ◽  
Mass Reduction ◽  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Hcl Solution ◽  
Mixed Type Inhibitor

Abstract Aizoon extract used as anti-corrosion for stainless steel430 (SS430) in 2M hydrochloric acid solution. The mass reduction, electrochemical impedance, and potentiodynamic polarization were carried out to demonstrate the performance of Aizoon extract as corrosion resistance for SS430. Polarization revealed that the Aizoon extract is mixed type inhibitor with superiority to inhibiting the cathodic reaction. The inhibition percentage reaches 93% at 300 ppm extract. Adsorption of the extract on SS430 surface is regular with Langmuir adsorption model. Thermodynamic factors for adsorption and activation processes for SS430 dissolution were estimated and discussed. Furthermore, the SS430 surface is characterized using different techniques. The surface morphology of SS430 was tested utilizing several techniques. The experimental data were supported by the theoretical data.

scholarly journals Adsorption of hexavalent chromium ions from aqueous solutions using nano-chitin: kinetic, isotherms and thermodynamic studies

2021 ◽  
Vol 16 (2) ◽  
pp. 436-451
Author(s):  
Meghdad Sheikhi ◽  
Hassan Rezaei
Keyword(s):  
Aqueous Solutions ◽  
Correlation Coefficient ◽  
Hexavalent Chromium ◽  
Contact Time ◽  
New Technology ◽  
Kinetic Studies ◽  
Chromium Vi ◽  
Effects Of Ph ◽  
Pseudo Second Order ◽  
Adsorbent Dose

Abstract Treatment of the industrial wastewater before discharging into aquatic ecosystems using a new technology such as nanotechnology seems necessary. There are different methods for the removal of the heavy metals in the wastewater. In this study, nano-chitin was purchased from the Nano-Novin Polymer Company and used as an adsorbent for the removal of chromium (VI) ions from aqueous solution in a batch system. The effects of pH, temperature, contact time, concentration, and adsorbent dose were investigated. According to the results, the optimum conditions of adsorption occurred at pH = 6, temperature = 25 °C, 60 minutes contact time, and 0.6 g·L−1 adsorbent dose. Investigation of equilibrium isotherms showed that the isotherm fitted the Freundlich model with a correlation coefficient of R2 = 0.9689. The pseudo second-order model with the larger correlation coefficient had a greater fitness against experimental data in the kinetic studies. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy were calculated, which indicated spontaneous, endothermic, and random processes, respectively. Given the good results of this project, nano-chitin can be suggested as a novel adsorbent which is highly capable of adsorbing hexavalent chromium from aqueous solutions.

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