Mercury (II) adsorption from aqueous solution using nitrogen and sulfur co-doped activated carbon

Abstract Activated carbon (AC) was modified with urea, thioglycolic acid and thiourea to obtain nitrogen doped activated carbon (ACN), sulfur doped activated carbon (ACS) and nitrogen and sulfur co-doped activated carbon (ACNS), respectively. The AC samples were characterized by elemental analysis, N2 adsorption-desorption, determination of the pH of the point of zero charge (pHpzc) and X-ray photoelectron spectroscopy, and tested for adsorption behaviors of Hg(II) ions. The experimental data of equilibrium isotherms fitted well with the Langmuir model. ACNS showed the highest adsorption capacity of 511.78 mg/g, increasing more than 2.5 times compared to the original ACA. The adsorption process followed pseudo-second-order kinetics. The thermodynamic parameters of ΔH°, ΔS°, and ΔG° at 30 °C were −20.57 kJ/mol, −0.032 kJ/mol K and −10.87 kJ/mol, respectively. It was concluded that the Hg(II) ions' adsorption on ACNS was exothermic, spontaneous and physiosorptive in nature. Finally, the adsorption capacity of ACNS reduced by just 8.13% even after the sixth cycle compared to the initial cycle.

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Efficient adsorption of Hg(II) from aqueous solution by N, S co-doped MnFe2O4@C magnetic nanoparticles

Water Science & Technology ◽

10.2166/wst.2020.224 ◽

2020 ◽

Vol 81 (6) ◽

pp. 1273-1282 ◽

Cited By ~ 1

Author(s):

Hangdao Qin ◽

Hao Cheng ◽

Chenggui Long ◽

Xiaogang Wu ◽

Yanhong Chen ◽

...

Keyword(s):

Magnetic Nanoparticles ◽

Chemical Properties ◽

Point Of Zero Charge ◽

Simple Method ◽

Transmission Electron ◽

Pseudo Second Order ◽

Enhanced Adsorption ◽

Adsorption Desorption ◽

Physical And Chemical ◽

Co Doped

Abstract N, S co-doped MnFe2O4@C magnetic nanoparticles were successfully synthesized by a simple method involving the preparation of MnFe2O4 nanoparticles and subsequent pyrolysis treatment. The physical and chemical properties of MnFe2O4, MnFe2O4@C and MnFe2O4@C–NS nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), N2 adsorption–desorption and the pH at the point of zero charge. Their performances in the adsorption of Hg(II) from water were investigated. The adsorption process followed pseudo-second-order kinetics and the experimental data of equilibrium isotherms fitted well with the Langmuir model. MnFe2O4@C–NS showed the highest adsorption capacity of 108.56 mg/g, increasing more than 1.7 times compared to MnFe2O4. The enhanced adsorption performance was attributed to the larger specific surface area as well as the complexation of N and S ligands on the surface. The thermodynamic parameters of ΔH°, ΔS° and ΔG° at 30 °C were −24.39 kJ/mol, −0.046 kJ/mol K and −10.45 kJ/mol, respectively, which indicated that the adsorption of Hg(II) on MnFe2O4@C–NS was exothermic and spontaneous in nature. Moreover, MnFe2O4@C–NS showed superior selectivity towards Hg(II) compared with other metal ions generally present in mercury-containing industrial wastewater.

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Removal of Mercury(II) from Aqueous Solutions by Adsorption on Poly(1-amino-5-chloroanthraquinone) Nanofibrils: Equilibrium, Kinetics, and Mechanism Studies

Journal of Nanomaterials ◽

10.1155/2016/7245829 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 13

Author(s):

Shaojun Huang ◽

Chengzhang Ma ◽

Yaozu Liao ◽

Chungang Min ◽

Ping Du ◽

...

Keyword(s):

Aqueous Solutions ◽

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Batch Adsorption ◽

Pseudo Second Order ◽

Ft Ir ◽

Repeated Use ◽

Real Wastewater ◽

Adsorption Desorption ◽

Order Rate Equation

Poly(1-amino-5-chloroanthraquinone) (PACA) nanofibrils were applied as novel nanoadsorbents for highly toxic mercury removal from aqueous solutions. A series of batch adsorption experiments were conducted to study the effect of adsorbent dose, pH, contact time, and metal concentration on Hg(II) uptake by PACA nanofibrils. Kinetic data indicated that the adsorption process of PACA nanofibrils for Hg(II) achieved equilibrium within 2 h following a pseudo-second-order rate equation. The adsorption mechanism of PACA nanofibrils for Hg(II) was investigated by Fourier transform-infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS) analyses. The adsorption isotherm of Hg(II) fitted well the Langmuir model, exhibiting superb adsorption capacity of 3.846 mmol of metal per gram of adsorbent. Lastly, we found out that the as-synthesized PACA nanofibrils are efficient in Hg(II) removal from real wastewater. Furthermore, five consecutive adsorption-desorption cycles demonstrated that the PACA nanofibrils were suitable for repeated use without considerable changes in the adsorption capacity.

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Mass-transfer processes in the adsorption of crystal violet by activated carbon derived from pomegranate peels: Kinetics and thermodynamic studies

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925020919847 ◽

2020 ◽

Vol 15 ◽

pp. 155892502091984

Author(s):

Moussa Abbas ◽

Zahia Harrache ◽

Mohamed Trari

Keyword(s):

Activated Carbon ◽

Adsorption Capacity ◽

Crystal Violet ◽

Agitation Speed ◽

Second Order ◽

Point Of Zero Charge ◽

Order Kinetic ◽

Solution Ph ◽

Pseudo Second Order ◽

Adsorbent Dose

This study investigates the potential use of activated carbon, prepared from pomegranate peels, as an adsorbent activated using H3PO4 and its ability to remove crystal violet from an aqueous solution. The adsorbent was characterized by the Brunauer–Emmett–Teller method (specific surface area: 51.0674 m2 g−1) and point of zero charge (pHPZC = 5.2). However, some examined factors were found to have significant impacts on the adsorption capacity of activated carbon derived from pomegranate peels such as the initial dye concentration (5–15 mg L−1), solution pH (2–14), adsorbent dose (1–8 g L−1), agitation speed (100–700 r/min), and temperature (298–338 K). The best adsorption capacity was found at pH 11 with an adsorbent dose of 1 g L−1, an agitation speed at 400 r/min, and a contact time of 45 min. The adsorption mechanism of crystal violet onto activated carbon derived from pomegranate peels was studied using the pseudo-first-order, pseudo-second-order, Elovich, and Webber–Morris diffusion models. The adsorption kinetics were found to rather follow a pseudo-second order kinetic model with a determination coefficient ( R2) of 0.999. The equilibrium adsorption data for crystal violet adsorbed onto activated carbon derived from pomegranate peels were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation with qmax capacities of 23.26 and 76.92 mg g−1 at 27°C and 32°C, respectively. The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters like the free energy, enthalpy, and entropy to predict the nature of adsorption process. The negative values Δ G0 (−5.221 to −1.571 kJ mol−1) and Δ H0 (−86.141 kJ mol−1) indicate that the overall adsorption is spontaneous and exothermic with a physisorption process. The adsorbent derived from pomegranate peels was found to be very effective and suitable for the removal of reactive dyes from aqueous solutions, due to its availability, low-cost preparation, and good adsorption capacity.

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Efficient adsorption of benzoic acid from aqueous solution by nitrogen-containing activated carbon

Water Science & Technology ◽

10.2166/wst.2018.235 ◽

2018 ◽

Vol 2017 (3) ◽

pp. 686-694 ◽

Cited By ~ 1

Author(s):

Hangdao Qin ◽

Rong Xiao ◽

Renhui Zhang ◽

Jing Chen

Keyword(s):

Aqueous Solution ◽

Activated Carbon ◽

Benzoic Acid ◽

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Ph Value ◽

Point Of Zero Charge ◽

Dispersion Force ◽

Solution Ph ◽

Efficient Treatment

Abstract Adsorption is an efficient treatment process to remove benzoic acid from aqueous solution. In this study, nitrogen-containing surface groups were introduced onto activated carbon (AC) surface by modification with ammonium hydroxide, ammonium carbonate, melamine or urea. The nitrogen-containing AC samples were characterized using N2 adsorption-desorption, Boehm titration, determination of the pH of the point of zero charge (pHpzc) and X-ray photoelectron spectroscopy. The adsorption of benzoic acid from aqueous solution by nitrogen-containing AC has been studied. The Langmuir model fitted the experimental data of equilibrium isotherms better than the Freundlich model. At initial solution pH 2.1, the adsorption capacity was closely related with the amount of pyridinic and pyrrolic N on the AC surface, which indicated these two nitrogen-containing groups played an important part in the adsorption process. The enhancement of adsorption capacity was due to the strengthened π–π dispersion force between benzoic acid and the AC basal plane. Since the surface charge of AC as well as the existence form of benzoic acid varied with solution pH value, the adsorption capacity was found to be highest at pH 3.8 and dropped sharply at higher or lower pH values.

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Effect of Sodium Benzenesulfonate on SO42− Removal from Water by Polypyrrole-Modified Activated Carbon

Advances in Materials Science and Engineering ◽

10.1155/2021/1442506 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Feng Zhang ◽

Dong-Sheng Wang ◽

Fan Yang ◽

Tian-Yu Li ◽

Hong-Yan Li ◽

...

Keyword(s):

Activated Carbon ◽

Adsorption Capacity ◽

Granular Activated Carbon ◽

Langmuir Model ◽

Sulfate Adsorption ◽

Modified Activated Carbon ◽

Pseudo Second Order ◽

Acidic Conditions ◽

Adsorption Desorption ◽

Desorption Cycle

Sodium benzenesulfonate was doped into polypyrrole-modified granular activated carbon (pyrrole-FeCl3·(6H2O)-sodium benzenesulfonate-granular activated carbon; PFB-GAC) with the goal of improving the modified GAC’s ability to adsorb sulfate from aqueous solutions. At a GAC dosage of 2.5 g and a pyrrole concentration of 1 mol L−1, the adsorption capacity of PFB-GAC prepared using a pyrrole:FeCl3·(6H2O):sodium benzenesulfonate ratio of 1000 : 1500 : 1 reached 23.05 mg g−1, which was eight times higher than that for GAC and two times higher than that for polypyrrole-modified GAC without sodium benzenesulfonate. Adsorption was favored under acidic conditions and high initial sulfate concentrations. Doping with sodium benzenesulfonate facilitated polymerization to give polypyrrole. Sodium benzenesulfonate introduced more imino groups to the polypyrrole coating, and the N+ sites improved ion exchange of Cl− and SO42− and increased the adsorption capacity of sulfate. Adsorption to the PFB-GAC followed pseudo-second-order kinetics. The adsorption isotherm conformed to the Langmuir model, and adsorption was exothermic. Regeneration using a weak alkali (NH3·H2O), which released OH− slowly, caused less damage to the polypyrrole than using a strong alkali (NaOH) as the regeneration reagent. NH3·H2O at a concentration of 12 mol L−1 (with the same OH− concentration as 2 mol L−1 NaOH) released 85% of the sorbed sulfate in the first adsorption-desorption cycle, and the adsorption capacity remained >6 mg g−1after five adsorption-desorption cycles.

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Biochar of Spent Coffee Grounds as Per Se and Impregnated with TiO2: Promising Waste-Derived Adsorbents for Balofloxacin

Molecules ◽

10.3390/molecules26082295 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2295

Author(s):

Marwa El-Azazy ◽

Ahmed S. El-Shafie ◽

Hagar Morsy

Keyword(s):

Adsorption Capacity ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

Spent Coffee Grounds ◽

Thermal Stabilities ◽

Coffee Grounds ◽

Bet Analysis ◽

Pseudo Second Order ◽

Set Up ◽

Adsorption Desorption

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO2@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO2 has increased the surface area (50.54 m2/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO2@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (qmax) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO2@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles.

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Preparation of bio-absorbents by modifying licorice residue via chemical methods and removal of copper ions from wastewater

Water Science & Technology ◽

10.2166/wst.2021.463 ◽

2021 ◽

Author(s):

Xiaochun Yin ◽

Nadi Zhang ◽

Meixia Du ◽

Hai Zhu ◽

Ting Ke

Keyword(s):

Adsorption Capacity ◽

Copper Ions ◽

Order Kinetic ◽

Solution Ph ◽

Chemical Methods ◽

Simple Strategy ◽

Order Kinetic Model ◽

Pseudo Second Order ◽

Surface Active ◽

Adsorption Desorption

Abstract In this paper, a series of bio-adsorbents (LR-NaOH, LR-Na2CO3 and LR-CA) were successfully prepared by modifying Licorice Residue with NaOH, Na2CO3 and citric acid, which were used as the adsorbents to remove Cu2+ from wastewater. The morphology and structure of bio-adsorbents were characterized by Fourier Transform Infrared, SEM, TG and XRD. Using static adsorption experiments, the effects of the adsorbent dosage, the solution pH, the adsorption time, and the initial Cu2+ concentration on the adsorption performance of the adsorbents were investigated. The results showed that the adsorption process of Cu2+ by the bio-adsorbents can be described by pseudo-second order kinetic model and the Langmuir model. The surface structure of the LR-NaOH, LR-Na2CO3 and LR-CA changed obviously, and the surface-active groups increased. The adsorption capacity of raw LR was 21.56 mg/g, LR-NaOH, LR- Na2CO3 significantly enhanced this value up to 43.65 mg/g, 43.55 mg/g, respectively. After four adsorption-desorption processes, the adsorption capacity of LR-NaOH also maintained about 73%. Therefore, LR-NaOH would be a promising adsorbent for removing Cu2+ from wastewater, and the simple strategy towards preparation of adsorbent from the waste residue can be as a potential approach using in the water treatment.

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Recovery of phosphate from aqueous solution by magnetically recycled modified polishing powder composites

Water Science & Technology ◽

10.2166/wst.2019.381 ◽

2019 ◽

Vol 80 (7) ◽

pp. 1357-1366

Author(s):

Jianming Liu ◽

Runying Bai ◽

Junfeng Hao ◽

Bowen Song ◽

Yu Zhang ◽

...

Keyword(s):

Adsorption Capacity ◽

Ligand Exchange ◽

Adsorption Process ◽

High Adsorption ◽

Order Model ◽

Powder Composites ◽

Langmuir Isotherm Model ◽

Pseudo Second Order ◽

Ph Level ◽

Adsorption Desorption

Abstract This study investigated a magnetically recycled modified polishing powder (CMIO@PP) as an adsorbent of phosphate; the CMIO@PP was synthesized by combining the modified La/Ce-containing waste polishing powder with CaO2-modified Fe3O4 (CMIO). Results indicate that the CMIO@PP nanocomposite presents a crystal structure comprising La (OH)3, Ce (OH)3, and Fe3O4, and that CMIO is uniformly dispersed in the modified polishing powder. The CMIO@PP (1:3) is a suitable choice considering its magnetism and adsorption capacity. The magnetic adsorbent exhibits a high adsorption capacity of 53.72 mg/g, a short equilibrium time of 60 min, and superior selectivity for phosphate. Moreover, the adsorbent strongly depends on the pH during the adsorption process and maintains a large adsorption capacity when the pH level is between 2 and 6. The adsorption of phosphate by the CMIO@PP (1:3) accords with the Langmuir isotherm model, and the adsorption process follows the pseudo-second order model. Meanwhile, adsorption–desorption experiments show that the adsorbent could be recycled a few times and that a high removal efficiency of phosphate from civil wastewater was achieved. Finally, mechanisms show that the adsorption of phosphate by the CMIO@PP (1:3) is mainly caused by electrostatic attraction and ligand exchange.

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Fabrication of Cellulose Nanocrystal-g-Poly(Acrylic Acid-Co-Acrylamide) Aerogels for Efficient Pb(II) Removal

Polymers ◽

10.3390/polym12020333 ◽

2020 ◽

Vol 12 (2) ◽

pp. 333 ◽

Cited By ~ 4

Author(s):

Yifan Chen ◽

Qian Li ◽

Yujie Li ◽

Qijun Zhang ◽

Jingda Huang ◽

...

Keyword(s):

Acrylic Acid ◽

Adsorption Capacity ◽

Langmuir Model ◽

Cellulose Nanocrystal ◽

Effective Removal ◽

Pseudo Second Order ◽

Repeated Use ◽

Adsorption Desorption ◽

Hydrolysis Of ◽

Poly Acrylic Acid

In this work, cellulose nanocrystals (CNCs) obtained by the acid hydrolysis of waste bamboo powder were used to synthesize cellulose nanocrystal-g-poly(acrylic acid-co-acrylamide) (CNC-g-P(AA/AM)) aerogels via graft copolymerization followed by freeze-drying. The structure and morphology of the resulting aerogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM), and the CNC-g-P(AA/AM) aerogels exhibited excellent absorbent properties and adsorption capacities. Subsequent Pb(II) adsorption studies showed that the kinetic data followed the pseudo-second-order equation, while the adsorption isotherms were best described using the Langmuir model. The maximum Pb(II) adsorption capacity calculated by the Langmuir model reached up to 366.3 mg/g, which is a capacity that outperformed that of the pure CNC aerogel. The CNC-g-P (AA/AM) aerogels become structurally stable through chemical cross-linking, which enabled them to be easily regenerated in HCl solution and retain the adsorption capacity after repeated use. The aerogels were found to maintain 81.3% removal efficiency after five consecutive adsorption–desorption cycles. Therefore, this study demonstrated an effective method for the fabrication of an aerogel adsorbent with an excellent reusability in the effective removal of Pb(II) from aqueous solutions.

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Preparation of Nano-Porous Carbon-Silica Composites and Its Adsorption Capacity to Volatile Organic Compounds

Processes ◽

10.3390/pr8030372 ◽

2020 ◽

Vol 8 (3) ◽

pp. 372 ◽

Cited By ~ 3

Author(s):

Lipei Fu ◽

Jiahui Zhu ◽

Weiqiu Huang ◽

Jie Fang ◽

Xianhang Sun ◽

...

Keyword(s):

Activated Carbon ◽

Volatile Organic Compounds ◽

Adsorption Capacity ◽

Organic Compounds ◽

Retention Rate ◽

Reaction System ◽

Carbon Powder ◽

Volatile Organic ◽

Adsorption Desorption ◽

Better Than

Carbon-silica composites with nanoporous structures were synthesized for the adsorption of volatile organic compounds (VOCs), taking tetraethyl orthosilicate (TEOS) as the silicon source and activated carbon powder as the carbon source. The preparation conditions were as follows: the pH of the reaction system was 5.5, the hydrophobic modification time was 50 h, and the dosage of activated carbon was 2 wt%. Infrared spectrum analysis showed that the activated carbon was dispersed in the pores of aerogel to form the carbon-silica composites material. The static adsorption experiments, dynamic adsorption-desorption experiments, and regeneration experiments show that the prepared carbon-silica composites have microporous and mesoporous structures, the adsorption capacity for n-hexane is better than that of conventional hydrophobic silica gel, and the desorption performance is better than that of activated carbon. It still has a high retention rate of adsorption capacity after multiple adsorption-desorption cycles. The prepared carbon-silica composites material has good industrial application prospects in oil vapor recovery, providing a new alternative for solving organic waste gas pollution.

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