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

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2858 ◽  
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.

Preparation of Graphene Oxide Modified Rice Husk for Cr(VI) Removal

2019 ◽  
Vol 19 (11) ◽  
pp. 7035-7043 ◽  
Author(s):  
Tong Ouyang ◽  
Jidan Tang ◽  
Fang Liu ◽  
Chang-Tang Chang
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Sites ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Alkaline Conditions ◽  
Rice Husk Biochar

The objective of this paper is to study the removal of Cr(VI) in aqueous solution by using a new graphene oxide-coated rice husk biochar composite (GO-RHB). GO-RHB is a synthetic material having a porous structure with lots of oxygen-containing functional groups and a large surface area that provide effective adsorption sites. Experiments showed that GO-RHB had higher adsorption capacity under acidic than under alkaline conditions. At pH of 2, GO-RHB has the maximum adsorption capacity(48.8 mg g−1). Equilibrium data obtained by fitting with the Langmuir and Freundlich models indicate that the reaction process was monolayer adsorption. The adsorption of Cr(VI) followed the pseudo-second-order kinetic model that illustrates chemical adsorption. Intraparticlediffusion studies further revealed that film diffusion was taking place. Moreover, the results of thermodynamics showed that the adsorption process was endothermic and spontaneous in nature. The removal mechanism of Cr(VI) was also explained in detail. The prepared adsorbent is highly efficient and might be useful than many other conventional adsorbent used for the removal of Cr(VI) from wastewater.

scholarly journals Effects of Cu(II) on the Adsorption Behaviors of Cr(III) and Cr(VI) onto Kaolin

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Juanjuan Liu ◽  
Xiaolong Wu ◽  
Yandi Hu ◽  
Chong Dai ◽  
Qin Peng ◽  
...  
Keyword(s):  
Distribution Coefficient ◽  
Adsorption Capacity ◽  
Removal Efficiency ◽  
Saturation Index ◽  
Surface Complexation ◽  
Maximum Adsorption Capacity ◽  
Positive Correlation ◽  
Adsorption Sites ◽  
Ph Values ◽  
Adsorption Behaviors

The adsorption of Cr(III) or Cr(VI) in the absence and presence of Cu(II) onto kaolin was investigated under pH 2.0–7.0. Results indicated that the adsorption rate was not necessarily proportional to the adsorption capacity. The solutions’ pH values played a key role in kaolin zeta potential(ζ), especially the hydrolysis behavior and saturation index of heavy metal ions. In the presence of Cu(II),qmixCr(III)reached the maximum adsorption capacity of 0.73 mg·g−1at pH 6.0, while the maximum adsorption capacity for the mixed Cr(VI) and Cu(II) system (qmixCr(VI)) was observed at pH 2.0 (0.38 mg·g−1). Comparing the adsorption behaviors and mechanisms, we found that kaolin prefers to adsorb hydrolyzed products of Cr(III) instead of Cr3+ion, while adsorption sites of kaolin surface were occupied primarily by Cu(II) through surface complexation, leading to Cu(II) inhibited Cr(VI) adsorption. Moreover, Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficientKd. Cr(III) and Cr(VI) removal efficiency had a positive correlation with distribution coefficientKdand that of adsorption affinities of Cr(III) or Cr(VI) on kaolin was found to beKdCr(III) <KdCr(III)-Cu(II) andKdCr(VI) >KdCr(VI)-Cu(II).

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

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.

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

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2264 ◽  
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.

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

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.

Removal properties of arsenic compounds with synthetic hydrotalcite compounds

2005 ◽  
Vol 5 (5) ◽  
pp. 75-81 ◽  
Author(s):  
Y. Kiso ◽  
Y. J. Jung ◽  
T. Yamada ◽  
M. Nagai ◽  
K. S. Min
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Inorganic Arsenic ◽  
Underground Water ◽  
Experimental Result ◽  
Maximum Adsorption Capacity ◽  
Arsenic Compounds ◽  
Adsorption Sites ◽  
Effects Of Ph ◽  
Very High

The contamination of underground water with inorganic arsenic compounds has caused serious problems, particularly in developing countries. For water containing low-level arsenic compounds, an adsorption process may be more effective than other processes such as RO membrane and precipitation. In this study, the removal performance for arsenic compounds was examined with synthetic hydrotalcite (HTAL) compounds as an adsorbent process from the following viewpoints: the adsorption capacity, adsorption isotherm, the effects of pH and co-existing anions. The HTAL-Cl, which contains Cl− ions as an intercalate, showed very high adsorption capacity in the neutral pH region. The maximum adsorption capacity was 105 mg-As(V) g−1. The adsorption isotherm was approximated by the following modified Langmuir equation:The equation suggests that one mol of As(V) occupies two adsorption sites of HTAL-Cl, and the experimental result indicated that 2.64 mol of Cl− ions in the HTAL-Cl were substituted with one mol of As(V). The interfering effects of co-existing anions were relatively low, and the magnitude of the effects was observed in the order of HCO3− &gt; HPO42− &gt; SO42− &gt; Cl−.

scholarly journals Three-dimensional double-network hydrogels of graphene oxide, alginate, and polyacrylonitrile for copper removal from aqueous solution

2019 ◽  
Vol 25 (6) ◽  
pp. 924-929 ◽  
Author(s):  
Jung-Weon Choi ◽  
Hee Jin Kim ◽  
Hayeon Ryu ◽  
Sanghwa Oh ◽  
Sang-June Choi
Keyword(s):  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Adsorption Equilibrium ◽  
Three Dimensional ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Double Network ◽  
Adsorption Sites ◽  
Pseudo Second Order ◽  
Ft Ir

Three-dimensional (3D) double-network graphene oxide/alginate-polyacrylonitrile (GO/Ca-Alg2-PAN) composite hydrogels were synthesized via surface functionalization of GO to activate adsorption sites. The morphology and structure of the GO/Ca-Alg2-PAN were analyzed by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA-DSC). The results of the physicochemical analyses indicated that GO/Ca-Alg2-PAN was successfully synthesized by the combination of a 2D-structured graphene oxide with the alginate which was functionalized with the PAN polymer to generate the 3D double network composites. This functionalization approach contributed to an increase in Cu<sup>2+</sup> ion adsorption capacity. The maximum adsorption capacity of the GO/Ca-Alg2-PAN for Cu<sup>2+</sup> was 5.99 mmol/g. The results of adsorption kinetic experiments indicated that the GO/Ca-Alg2-PAN reached adsorption equilibrium within 147 mins at 2 mM Cu<sup>2+</sup> in accordance with a pseudo-second-order model.

scholarly journals Cu(II) and Cd(II) Removal from Aqueous Solution with LDH@GO-NH2 and LDH@GO-SH: Kinetics and Probable Mechanism

2021 ◽  
Author(s):  
Wei Liao ◽  
Di Bao ◽  
Huiqiang Li ◽  
Ping Yang
Keyword(s):  
Adsorption Capacity ◽  
Thiol Group ◽  
Maximum Adsorption Capacity ◽  
Isomorphic Substitution ◽  
Temperature Dependent ◽  
Adsorption Mechanisms ◽  
Adsorption Processes ◽  
Endothermic Process ◽  
Pseudo Second Order ◽  
Near Future

Abstract Two novel adsorbents of thiol- and amino-functionalized GO grafted onto LDH (LDH@GO-NH2 and LDH@GO-SH) were synthesized and contrasted for adsorption properties for Cu(II) and Cd(II). Characterization experiments illustrated that thiol group (-SH) and amino group (-NH2) were existed onto LDH@GO-NH2 and LDH@GO-SH. Adsorption isotherm results showed that the adsorption processes were satisfactorily fitted by both Langmuir and Freundlich models. The maximum adsorption capacity of Cd(II) on LDH@GO-SH at 308 K was 102.77 mg/g, which was about triple that of LDH@GO-NH2. The enhancement in adsorption capacity was due to the cooperative effect of LDH and GO-SH. The kinetic experimental data for LDH@GO-NH2 and LDH@GO-SH were found to be in good agreement with pseudo-second-order model. The thermodynamic parameters calculated from the temperature dependent adsorption isotherms indicated that the adsorption was a spontaneous and endothermic process. The possible adsorption mechanisms comprising formation of precipitation, isomorphic substitution of Mg(II), and formation of complexation with amino-groups and thiol-groups were proposed. Desorption experiments put into evidence that the LDH@GO-NH2 and LDH@GO-SH may be promising suitable candidates for the remediation of metal ions from aqueous solutions in real work in the near future.

scholarly journals GO/PAMAM as a High Capacity Adsorbent for Removal of Alizarin Red S: Selective Separation of Dyes

2020 ◽  
Vol 67 (4) ◽  
pp. 1124-1138
Author(s):  
Mohammad Rafi ◽  
Babak Samiey ◽  
Chil-Hung Chen
Keyword(s):  
Adsorption Capacity ◽  
High Capacity ◽  
Pamam Dendrimer ◽  
Alizarin Red S ◽  
Alkaline Media ◽  
Maximum Adsorption Capacity ◽  
Alizarin Red ◽  
Adsorption Sites ◽  
Diffusion Controlled ◽  
Amine Groups

Adsorption of Alizarin Red S (ARS) on graphene oxide/poly(amidoamine) (GO/PAMAM) was studied at different ARS initial concentrations, temperatures, pHs, shaking rates and contact times. Adsorption sites of GO/PAMAM were phenolic –OH (Ph) group of GO and amine groups (–NH2, –NH+ 3 and –NHR+2) of PAMAM dendrimer moieties of GO/PAMAM. At pH = 2 and 318 K, maximum adsorption capacity (qe,max) of the adsorbent was 1275.2 mg g–1 which is one of the highest capacity in the literature. Thus, GO/PAMAM in this work acted as a superadsorbent for ARS. At the incipient of adsorption, ARS– molecules were adsorbed on Ph sites that was reaction-controlled step, (Ea = 114.5 kJ mol–1). Adsorption of ARS–on the remaining sites was diffusion–controlled. In alkaline media, two other types of ARS molecules were identified during that were adsorbed on Ph and –NH+ 3 sites. Further increasing the pH of the solution, decreased the number these two sites and yielded a reduced adsorption capacity (qe,max). Methylene blue (MB), thionine (Th), pyronin Y (PY), acridine orange (AO), methyl blue (MEB) and janus green (JG) dyes were selectively separated from their mixtures with ARS molecules using GO/PAMAM at pH of 2. The used adsorbent was recycled fficiently by using ethylenediamine very fast.

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

2010 ◽  
Vol 67 (3) ◽  
pp. 301-307 ◽  
Author(s):  
Cindy Silva Moreira ◽  
Luís Reynaldo Ferracciú Alleoni
Keyword(s):  
Adsorption Capacity ◽  
Tropical Soils ◽  
Langmuir Model ◽  
Tropical Region ◽  
Maximum Adsorption Capacity ◽  
Competitive System ◽  
Adsorption Mechanisms ◽  
Competitive Systems ◽  
Metal Affinity ◽  
Surface Samples

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.

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