Adsorption of Cd, Cu, Ni and Zn in tropical soils under competitive and non-competitive systems

The adsorption of heavy metals in soils affects their behavior in the environment and their bioavailability to plants. The knowledge of the adsorption mechanisms in competitive systems allows a more realistic evaluation of the metals' behavior in the soil than the single metal adsorption. The objectives of this study were (i) to evaluate Cd, Cu, Ni, and Zn adsorption in 14 surface samples (0-0.2 m) of representative soils of the Brazilian humid-tropical region, in competitive and non-competitive systems, and (ii) to establish metal affinity sequences for each soil, based in the maximum adsorption capacity (MAC) estimated by the Langmuir model. The Rhodic Eutrudox, the Kandiudalf Eutrudox, the Arenic Hapludalf, the Arenic Hapludult and the Typic Argiudoll had the highest metals' adsorption capacity, whereas the Typic Quartzipsamment and the sandy-textured Arenic Hapludult had the lowest values. In general, the MAC values for metals were lower in the competitive than in the non-competitive system. In the non-competitive system, the most common affinity sequence was Cu > Zn > Ni > Cd, whereas the most common sequence was Cu > Cd > Zn > Ni in the competitive system. In general, the Langmuir model fitted well the adsorption data of metals on the studied soils.

Download Full-text

The Triple Mechanisms of Atenolol Adsorption on Ca-Montmorillonite: Implication in Pharmaceutical Wastewater Treatment

Materials ◽

10.3390/ma12182858 ◽

2019 ◽

Vol 12 (18) ◽

pp. 2858 ◽

Cited By ~ 2

Author(s):

Po-Hsiang Chang ◽

Wei-Teh Jiang ◽

Binoy Sarkar ◽

Wendong Wang ◽

Zhaohui Li

Keyword(s):

Adsorption Capacity ◽

Clay Mineral ◽

Basal Spacing ◽

Maximum Adsorption Capacity ◽

Pharmaceutical Wastewater ◽

Absorption Bands ◽

Adsorption Mechanisms ◽

Adsorption Sites ◽

Dioctahedral Smectite ◽

Β Receptor

The adsorption of atenolol (AT) from aqueous solutions by Ca-montmorillonite (SAz-2) was investigated in batch studies under different physicochemical conditions. The AT existed in neutral un-dissociated form at pH 10, and was adsorbed on dioctahedral smectite (SAz-2) obeying the Langmuir isotherm with a maximum adsorption capacity of 330 mmol/kg. The kinetic adsorption suggested that both strong and weak adsorption sites existed on SAz-2 and participated in the adsorption mechanisms. The amount of exchangeable cations desorbed from SAz-2 during AT adsorption was linearly correlated with the amounts of adsorbed AT having slopes of 0.43, which implied that a cation exchange based adsorption mechanism was also in place. A comprehensive basal spacing change of SAz-2 was observed after AT adsorption on the clay mineral when tested with or without AT recrystallization. The intercalation of AT into the SAz-2 interlayers did not result in swelling due to the low adsorption capacity of the drug. Prominent interactions between the pharmaceutical molecule and SAz-2 were evidenced by apparent shifts of the infrared absorption bands after adsorption. The interlayer configurations and hydrogen bonding of AT on SAz-2 were also supported by infrared, X-ray diffraction and thermogravimetric analyses. This study suggested that SAz-2 is an excellent material to remove not only AT from pharmaceutical wastewater, but can potentially remove many other β-receptor blocker drugs. The results helped us to understand the possible interlayer configurations and adsorption mechanisms of the drugs on natural clay mineral based adsorbents.

Download Full-text

Investigation of adsorption capacity of N-carboxymethyl chitosan for Pb(II) ions

Water Science & Technology ◽

10.2166/wst.2013.438 ◽

2013 ◽

Vol 68 (8) ◽

pp. 1873-1879 ◽

Cited By ~ 1

Author(s):

Chongxia Wang ◽

Qingping Song ◽

Jiangang Gao

Keyword(s):

Adsorption Capacity ◽

Ph Value ◽

Chloroacetic Acid ◽

Freundlich Isotherm ◽

Carboxymethyl Chitosan ◽

Langmuir Model ◽

Second Order ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

First Order

N-carboxymethyl chitosan (NCMC) was prepared by reacting chitosan (CTS) with chloroacetic acid and characterized by 13C-NMR spectroscopy to confirm that carboxymethylation occurred only in the amino groups. The adsorption properties of CTS, NCMC and O-carboxymethyl chitosan (OCMC) towards Pb(II) ions were evaluated and the order of the adsorption capacity was as follows: NCMC > OCMC > CTS. The effects of initial pH value (2.0–5.5) of the solutions and contact time (5–120 min) on adsorption of Pb(II) were investigated and the kinetic data were evaluated using the pseudo-first-order and pseudo-second-order models. Kinetics study showed that the adsorption process followed second-order kinetics rather than the first-order one. Furthermore, the experimental equilibrium data of Pb(II) on the NCMC were analyzed using the Langmuir and Freundlich isotherm models and the results indicated that the Langmuir model gave a better fit than the Freundlich equation and the maximum adsorption capacity obtained from the Langmuir model was 421.9 mg g−1.

Download Full-text

Preparation of GO/MIL-101(Fe,Cu) composite and its adsorption mechanisms for phosphate in aqueous solution

10.21203/rs.3.rs-191207/v1 ◽

2021 ◽

Author(s):

You Wu ◽

Zuannian Liu ◽

Bakhtari Mohammad Fahim ◽

Junnan Luo

Keyword(s):

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Adsorption Mechanism ◽

Nitrogen Adsorption ◽

Adsorption Properties ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

X Ray ◽

Adsorption Mechanisms ◽

Adsorption Desorption

Abstract In this study, MIL-101(Fe), MIL-101(Fe,Cu), and Graphene Oxide (GO) /MIL-101(Fe,Cu) were synthesized to compose a novel sorbent. The adsorption properties of these three MOFs-based composites were compared toward the removal of phosphate. Furthermore, the influencing factors including reaction time, pH, temperature and initial concentration on the adsorption capacity of phosphate on these materials as well as the reusability of the material were discussed. The structure of fabricated materials and the removal mechanism of phosphate on the composite material were analyzed by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis and zeta potential. The results show that the maximum adsorption capacity of phosphate by the composite GO/MIL-101(Fe,Cu)-2% was 204.60 mg·g− 1, which is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe). likewise the specific surface area of GO/MIL-101(Fe,Cu)-2% is 778.11 m2/g is higher than that of MIL-101(Fe,Cu) and MIL-101(Fe),which are 747.75 and 510.66m2/g respectively. The adsorption mechanism of phosphate is electrostatic attraction, form coordination bonds and hydrogen bonds. The fabricated material is a promising adsorbent for the removal of phosphate with good reusability.

Download Full-text

Investigating the efficiency of single-walled and multi-walled carbon nanotubes in removal of penicillin G from aqueous solutions

Environmental Health Engineering and Management ◽

10.15171/ehem.2018.26 ◽

2018 ◽

Vol 5 (4) ◽

pp. 187-196 ◽

Cited By ~ 5

Author(s):

Soheila Chavoshan ◽

Maryam Khodadadi ◽

Negin Nasseh ◽

Ayat Hossein Panahi ◽

Aliyeh Hosseinnejad

Keyword(s):

Carbon Nanotubes ◽

Aqueous Solutions ◽

Adsorption Capacity ◽

Langmuir Model ◽

Penicillin G ◽

Maximum Adsorption Capacity ◽

Initial Concentration ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Kinetics Of

Background: Drugs, especially antibiotics, are one of the serious problems of modern life and the main pollution sources of the environment, especially in the last decade, which are harmful to human health and environment. The aim of this study was to investigate the removal of penicillin G from aqueous solutions using single-walled and multi-walled carbon nanotubes. Methods: In this study, the effect of different parameters including pH (3, 5, 7, 9, and 11), initial concentration of pollutant (50, 100, 150, and 200 mg/l), absorbent dose (0.25, 0.5, 0.75, and 1 g/L), mixing speed (0, 100, 200, and 300 rpm), and temperature (10, 15, 25, 35, 45°C) were investigated. The Langmuir, Freundlich, Temkin, BET, Dubinin-Radushkevich isotherms and adsorption kinetics of the first- and second-order equations were determined. Results: The results showed that the efficiency of single-walled and multi-walled carbon nanotubes in the removal of penicillin G was 68.25% and 56.37%, respectively, and adsorption capacity of the nanotubes was 141 mg/g and 119 mg/g at initial concentration of 50 mg/l and pH=5 with adsorption dose of 0.8 g/L for 105 minutes at 300 rpm and temperature of 10°C from aqueous solutions. Also, it was revealed that the adsorption process had the highest correlation with the Langmuir model and secondorder kinetics, and the maximum adsorption capacity based on Langmuir model was 373.80 mg/g. Conclusion: According to the results, it was found that single-walled and multi-walled carbon nanotubes can be used as effective absorbents in the removal of penicillin G from aqueous solutions.

Download Full-text

Surface Interactions during the Removal of Emerging Contaminants by Hydrochar-Based Adsorbents

Molecules ◽

10.3390/molecules25092264 ◽

2020 ◽

Vol 25 (9) ◽

pp. 2264 ◽

Cited By ~ 1

Author(s):

Silvia Román ◽

Joâo Manuel Valente Nabais ◽

Beatriz Ledesma ◽

Carlos Laginhas ◽

Maria-Magdalena Titirici

Keyword(s):

Nicotinic Acid ◽

Adsorption Capacity ◽

Emerging Contaminants ◽

Activated Carbons ◽

Surface Acidity ◽

Maximum Adsorption Capacity ◽

Adsorption Mechanisms ◽

Olive Stone ◽

Steric Factors ◽

Negative Ionization

The aim of this work was to test activated carbons derived from hydrochars produced from sunflower stem, olive stone and walnut shells, as adsorbents for emerging contaminants in aqueous solution, namely fluoxetine and nicotinic acid. The adsorption capacity was determined by the chemical nature of the adsorbents, namely the presence of specific functional groups and their positive or negative ionization in aqueous solutions and also by steric factors. The activated carbons produced by air showed a higher adsorption capacity of fluoxetine, whilst the samples produced by carbon dioxide activation were more useful to remove nicotinic acid. In general, surface acidity was advantageous for fluoxetine adsorption and detrimental for nicotinic acid removal. The adsorption mechanisms involved in each case were discussed and related to the adsorbents characteristics. The maximum adsorption capacity, Q0, given by the Langmuir model was 44.1 and 91.9 mg g−1 for fluoxetine and nicotinic acid adsorption, respectively.

Download Full-text

Linking phosphorus sorption and magnetic susceptibility in clays and tropical soils

Soil Research ◽

10.1071/sr20099 ◽

2020 ◽

Vol 58 (5) ◽

pp. 430 ◽

Cited By ~ 1

Author(s):

G. C. Poggere ◽

V. Barrón ◽

A. V. Inda ◽

J. Z. Barbosa ◽

A. D. B. Brito ◽

...

Keyword(s):

Magnetic Susceptibility ◽

Adsorption Capacity ◽

Tropical Soils ◽

Maximum Adsorption Capacity ◽

Phosphorus Sorption ◽

P Adsorption ◽

Opposite Trend ◽

Adsorption Data ◽

The Relationship ◽

P Desorption

Maghemite (Mh) and magnetic susceptibility have been little studied in relation to phosphorus (P) sorption, despite the fact that tropical soils – particularly those derived from mafic rocks – may contain substantial amounts of this iron oxide. In this work, we investigated the relationship between P adsorption and magnetic susceptibility in tropical soils, and determined the maximum adsorption capacity of P (MACP) and P desorption in seven pedogenic clays from magnetic soils with contrasting parent materials and three synthetic Mh samples. Considering the heterogeneity of the soil dataset in this study, the exclusive adoption of magnetic susceptibility as an indicator of P adsorption potential in soil remains uncertain. The relationship between magnetic susceptibility and adsorbed P was more evident in the B horizon of red soils from basic igneous rocks. In this group, soils with magnetic susceptibility above 20 × 10−6 m3 kg−1 had high adsorbed P. Although the pedogenic clays exhibited lower MACP values (1353–2570 mg kg–1) than the synthetic Mh samples (3786–4321 mg kg–1), P desorption exhibited the opposite trend (~14% vs ~8%). The substantial P adsorption capacity of synthetic Mh confirmed the adsorption data for pedogenic clays, which were strongly influenced by magnetic susceptibility, Mh and gibbsite contents, and specific surface area.

Download Full-text

Adsorption of lead using a novel xanthated carboxymethyl chitosan

Water Science & Technology ◽

10.2166/wst.2013.706 ◽

2013 ◽

Vol 69 (2) ◽

pp. 298-304 ◽

Cited By ~ 7

Author(s):

Qingping Song ◽

Chongxia Wang ◽

Ze Zhang ◽

Jiangang Gao

Keyword(s):

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Adsorption Mechanism ◽

Ph Value ◽

Carboxymethyl Chitosan ◽

Langmuir Model ◽

Maximum Adsorption Capacity ◽

Visible Spectra ◽

Initial Ph ◽

Uv Visible

Adsorption of Pb(II) was studied using a novel xanthated carboxymethyl chitosan (XCC). The XCC was synthesized using the xanthation reaction of N-carboxymethyl chitosan (NCMC). The chemical structure of XCC was characterized by UV–visible spectra. The effects of initial pH value of the solutions, contact time and adsorption isotherms on adsorption of Pb(II) were investigated. Moreover, the possible adsorption mechanism was identified using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The experimental results showed XCC experienced a high adsorption capacity. The adsorption isotherm followed the Langmuir model. The maximum adsorption capacity obtained from the Langmuir model was 520.8 mg/g. Thermodynamic studies revealed a spontaneous and exothermic adsorption process. FTIR and XPS studies showed that the carboxyl groups, nitrogen atoms and sulfur atoms participated in the adsorption of Pb(II).

Download Full-text

Fe(III) Complexed Polydopamine Modified Mg/Al Layered Double Hydroxide Enhances The Removal of Cr(VI) From Aqueous Solutions

10.21203/rs.3.rs-854606/v1 ◽

2021 ◽

Author(s):

Changcheng Chen ◽

Mina Luo ◽

Fu Chen ◽

Chao Huang ◽

Chunmei Zhu ◽

...

Keyword(s):

Aqueous Solutions ◽

Adsorption Capacity ◽

Maximum Adsorption Capacity ◽

X Ray Diffraction ◽

X Ray ◽

Adsorption Mechanisms ◽

Removal Capacity ◽

Double Hydroxide ◽

Double Hydroxides ◽

Influence Of Ph

Abstract Herein, we report the preparation of Fe(III) complexed polydopamine modified Mg/Al layered double hydroxides composite material (LDHs@PDA-Fe(III)) and its application to the removal of Cr(VI) in aqueous solution. LDHs@PDA-Fe(III) was characterized and analyzed by field-emission scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transformed infrared (FTIR), X-ray diffraction (XRD), X-ray photoelectron (XPS). The adsorption performance was studied through a series of adsorption experiments. Under the influence of pH, time, temperature, concentration, the maximum adsorption capacity obtained in the experiment is 683.4 mg/g. In addition, after 5 adsorption cycles, LDHs@PDA-Fe(III) still shows excellent adsorption capacity and stability. Combining adsorption experiments and characterization analysis, it is inferred that the adsorption of Cr(VI) by LDHs@PDA-Fe(III) is the result of the synergistic effect of multiple adsorption mechanisms. Therefore, the efficient removal capacity and excellent stability make LDHs@PDA-Fe(III) an ideal adsorbent for removing Cr(VI) from aqueous solutions.

Download Full-text

Efficient Removal 17-Estradiol by Graphene-Like Magnetic Sawdust Biochar: Preparation Condition and Adsorption Mechanism

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17228377 ◽

2020 ◽

Vol 17 (22) ◽

pp. 8377

Author(s):

Yahui Zhou ◽

Shaobo Liu ◽

Yunguo Liu ◽

Xiaofei Tan ◽

Ni Liu ◽

...

Keyword(s):

Kinetic Model ◽

Adsorption Capacity ◽

Adsorption Mechanism ◽

Langmuir Model ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

First Order ◽

Micropore Filling ◽

Order Kinetic Model ◽

Pseudo First Order

The occurrence of environmental endocrine disrupting chemicals (EDCs) in aquatic environments has caused extensive concern. Graphene-like magnetic sawdust biochar was synthesized using potassium ferrate (K2FeO4) to make activated sawdust biochar and applied for the removal of 17-estradiol (E2). The characterization showed that the surface morphology of five graphene-like magnetic sawdust biochars prepared with different preparation conditions were quite different. The specific surface area and pore structure increased with the increment of K2FeO4 addition. The results have shown that graphene-like magnetic sawdust biochar (1:1/900 °C) had the best removal on E2. The experimental results indicated that pseudo-first-order kinetic model and the Langmuir model could describe the adsorption process well, in which the equilibrium adsorption capacity (qe,1) of 1:1/900 °C were 59.18 mg·g−1 obtained from pseudo-first-order kinetic model and the maximum adsorption capacity (qmax) of 1:1/900 °C were 133.45 mg·g−1 obtained from Langmuir model at 298K. At the same time, lower temperatures, the presence of humic acid (HA), and the presence of NaCl could be regulated to change the adsorption reaction in order to remove E2. Adsorption capacity was decreased with the increase of solution pH because pH value not only changed the surface charge of graphene-like magnetic sawdust biochar, but also affected the E2 in the water. The possible adsorption mechanism for E2 adsorption on graphene-like magnetic sawdust biochar was multifaceted, involving chemical adsorption and physical absorption, such as H-bonding, π-π interactions, micropore filling effects, and electrostatic interaction. To sum up, graphene-like magnetic sawdust biochar was found to be a promising absorbent for E2 removal from water.

Download Full-text

Y2O3 functionalized natural palygorskite as an adsorbent for methyl blue removal

RSC Advances ◽

10.1039/c6ra04350j ◽

2016 ◽

Vol 6 (48) ◽

pp. 41765-41771 ◽

Cited By ~ 22

Author(s):

Xi He ◽

Jianjun Wang ◽

Zhan Shu ◽

Aidong Tang ◽

Huaming Yang

Keyword(s):

Wastewater Treatment ◽

Adsorption Isotherm ◽

Adsorption Capacity ◽

Langmuir Model ◽

Methyl Blue ◽

Maximum Adsorption Capacity ◽

Potential Applications

The methyl blue adsorption isotherm on Y2O3/Palygorskite obeys the Langmuir model, with the maximum adsorption capacity greatly enhanced to 1579.06 mg g−1, exhibiting potential applications in wastewater treatment.

Download Full-text