scholarly journals Sulfate Kinetics and Adsorption Studies on a Zeolite/Polyammonium Cation Composite for Environmental Remediation

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Carmen Pizarro ◽  
Mauricio Escudey ◽  
Camila Bravo ◽  
Manuel Gacitua ◽  
Lynda Pavez
Keyword(s):  
Ionic Strength ◽  
Adsorption Capacity ◽  
Natural Zeolite ◽  
Environmental Remediation ◽  
High Capacity ◽  
Ionic Species ◽  
Sulfide Mineral ◽  
Order Kinetic ◽  
Sulfate Adsorption ◽  
Order Kinetic Model

Sulfide mineral mining produces highly sulfate-contaminated wastewater which needs to be treated before disposal. A composite material was made from natural zeolite (NZ) and Superfloc® SC-581, a polyammonium cationic polymer. The resulting modified zeolite (MZ) demonstrated improved capacity for sulfate abatement from wastewater compared to NZ. Above pH 4.0, MZ retained positive surface charge while NZ remained negative. The effect of the ionic strength on the adsorption process was evaluated. Sulfate adsorption capacity was assessed and revealed MZ to be superior to NZ in all cases. Adsorption kinetics reached equilibrium after 10–12 h, with MZ adsorption being twice that of NZ; data fitted a pseudo-second order kinetic model. Adsorption isotherms reflected the high capacity of MZ for sulfate adsorption with maximum of 3.1 mg g−1, while NZ only achieved 1.5 mg g−1. The process corresponds to heterogeneous partially reversible adsorption of ionic species over the solid adsorbent. Langmuir–Freundlich parameters revealed that adsorption over MZ corresponds to an interaction eight times stronger than that on NZ. The sulfate adsorption pattern changes with ionic strength. Taken together, the composite formed between natural zeolite and polyammonium represents an adsorbent that maintains the adsorption capacity of zeolite and proves suitable for anionic species removal. Further prospect considers the testing of the composite with other anionic pollutants (arsenate, phosphate, perchlorate, etc.)

scholarly journals Semicarbazide Functionalized Flax Fibers for Effective Adsorption of Cr(VI) from Wastewater Samples

2021 ◽  
Author(s):  
Magda A. Akl ◽  
Mohamed Hashem ◽  
Aya G. Mostafa
Keyword(s):  
Ionic Strength ◽  
Adsorption Capacity ◽  
High Efficiency ◽  
Kinetic Studies ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Flax Fibers ◽  
Effects Of Ph ◽  
Order Kinetic Model ◽  
Wastewater Samples

<p>Semicarbazid modified flax fiber (SC.MFF) was successfully synthesized for the removal of Cr(IV) from different wastewater samples. Preparation of the SC.MFF material occurred in two main steps, the first step is the oxidation of the flax fibers by potassium periodate and the next step is refluxing of the oxidized fibers with semicarbazide ligand. The results show that quaternary ammonium cations were grafted on the surface of SC.MFF successfully. Additionally, a series of characterization of the SC.MFF sorbent was carried out using scanning electron microscopy, FTIR, elemental analysis, and X-ray diffraction spectroscopy. The effects of pH and ionic strength on the adsorption capacity were also investigated, which showed the adsorption capacity of the adsorbent decreased significantly with the increase of ionic strength and pH. Under optimized extraction conditions, the sorption capacity of Cr(VI) is 97.4 mg. g<sup>-1</sup>. The kinetic studies show that the experimental data matches well with the pseudo-second-order kinetic model. Furthermore, the studied Cr(VI) adsorbed on the sorbent according to the Langmuir adsorption model. Finally, the SC.MFF sorbent was successfully applied for the selective and high-efficiency recovery of Cr(VI) ions from different water samples. </p>

scholarly journals Semicarbazide Functionalized Flax Fibers for Effective Adsorption of Cr(VI) from Wastewater Samples

2021 ◽  
Author(s):  
Magda A. Akl ◽  
Mohamed Hashem ◽  
Aya G. Mostafa
Keyword(s):  
Ionic Strength ◽  
Adsorption Capacity ◽  
High Efficiency ◽  
Kinetic Studies ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Flax Fibers ◽  
Effects Of Ph ◽  
Order Kinetic Model ◽  
Wastewater Samples

<p>Semicarbazid modified flax fiber (SC.MFF) was successfully synthesized for the removal of Cr(IV) from different wastewater samples. Preparation of the SC.MFF material occurred in two main steps, the first step is the oxidation of the flax fibers by potassium periodate and the next step is refluxing of the oxidized fibers with semicarbazide ligand. The results show that quaternary ammonium cations were grafted on the surface of SC.MFF successfully. Additionally, a series of characterization of the SC.MFF sorbent was carried out using scanning electron microscopy, FTIR, elemental analysis, and X-ray diffraction spectroscopy. The effects of pH and ionic strength on the adsorption capacity were also investigated, which showed the adsorption capacity of the adsorbent decreased significantly with the increase of ionic strength and pH. Under optimized extraction conditions, the sorption capacity of Cr(VI) is 97.4 mg. g<sup>-1</sup>. The kinetic studies show that the experimental data matches well with the pseudo-second-order kinetic model. Furthermore, the studied Cr(VI) adsorbed on the sorbent according to the Langmuir adsorption model. Finally, the SC.MFF sorbent was successfully applied for the selective and high-efficiency recovery of Cr(VI) ions from different water samples. </p>

scholarly journals Removal of humic acid from aqueous solution using polyacrylamide/chitosan semi-IPN hydrogel

2018 ◽  
Vol 2017 (1) ◽  
pp. 16-26 ◽  
Author(s):  
Zejun Liu ◽  
Shaoqi Zhou
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Ionic Strength ◽  
Adsorption Capacity ◽  
Electrostatic Interactions ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Initial Ph ◽  
Wide Ph Range ◽  
Order Kinetic Model

Abstract In this study, we provide the first documented removal of humic acid (HA) from aqueous solution using polyacrylamide/chitosan (PAAm/CS) semi-IPN hydrogel. The prepared semi-IPN hydrogel was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The factors effecting HA adsorption performance were individually tested, including initial pH, ionic strength, contact time, initial HA concentration, and temperature. The results indicated that semi-IPN hydrogel was successfully fabricated and can be applied in a wide pH range, from 3 to 9. Low ionic strength effectively enhanced the adsorption capacity. As the ionic strength increased, this enhancement was less obvious but still positive. The adsorption kinetics were fitted to a pseudo-first-order kinetic model, and the adsorption isotherm was described using the Sips isotherm model. The HA adsorption capacity increased with increasing temperature. The maximum adsorption capacity has the potential to attain 166.30 mg g−1, based on the Sips isotherm at 25 °C. Experiments demonstrated that the HA adsorption process can be primarily attributed to electrostatic interactions, and hydrogen bonding was also involved. Facile synthesis and good adsorptive performance indicate that semi-IPN hydrogel can be used for removing HA from water.

scholarly journals Optimization of cadmium(II) adsorption onto modified and unmodified lignocellulosics (rice husk and egussi peeling)

2015 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Ngakou Sadeu Christian ◽  
Kamgaing Théophile ◽  
Ngomo Horace Manga ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Batch Technique ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Adsorbed Quantity ◽  
Minimal Mass ◽  
Modified Adsorbents

<p>The present study is based on the adsorption of cadmium (II) ions on rice husk and egussi peeling, unmodified and modified with nitric acid in aqueous solution, using batch technique. It was carried out as a function of contact time, dosage, pH and initial concentration. The equilibrium time was achieved within 25 minutes for unmodified rice husk (Glu NT) and 20 minutes for unmodified egussi peeling (Cuc NT) with an adsorbed quantity of 13.18 mg/g. In the case of modified materials, we obtained 15 minutes for modified rice husk (Glu HNO3) and 10 minutes for modified egussi peeling (Cuc HNO3) with an adsorbed quantity of 18.77 mg/g. The maximum biosorption occurred at pH 5.5 for all biosorbents. The adsorbent mass for maximum adsorption was 0.4 g giving an adsorption capacity of 62.02 % for unmodified adsorbents. In the case of modified adsorbents, the minimal mass at which maximum adsorption occurred was 0.4 g giving an adsorption capacity of 98.33 % and 0.6 g giving an adsorption capacity of 98.33 % for modified rice husk and egussi peeling respectively. The adsorbent/adsorbate equilibrium was well described by the pseudo-second order kinetic model and by Langmuir’s and Freundlich adsorption model. This models showed that the adsorption of cadmium (II) is a chemisorption process.</p>

Highly efficient carbonaceous nanofiber/layered double hydroxide nanocomposites for removal of U(VI) from aqueous solutions

2019 ◽  
Vol 107 (4) ◽  
pp. 299-309
Author(s):  
Shuqi Yu ◽  
Xiangxue Wang ◽  
Shunyan Ning ◽  
Zhongshan Chen ◽  
Xiangke Wang
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Layered Double Hydroxide ◽  
Photoelectron Spectroscopy ◽  
Environmental Remediation ◽  
Three Dimensional ◽  
Order Kinetic ◽  
Surface Bonding ◽  
Double Hydroxide ◽  
Shed Light

Abstract The three-dimensional (3D) carbonaceous nanofiber and Ni-Al layered double hydroxide (CNF/LDH) nanocomposite was successfully prepared by a facile one-step hydrothermal methodology. Characterization of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), XRD, and Fourier transformed infrared spectroscopy (FTIR) provided a demonstration that the modified CNF/LDH nanocomposite possessed abundant functional groups, for instance, metal-oxygen surface bonding sites (Ni–O as well as Al–O) and free-metal surface bonding sites (C–O, C–O–C, as well as O–C=O). The elimination of representative radionuclide (i.e. U(VI)) on the CNF/LDH nanocomposite from aqueous solutions was explored as a key function of pH, ionic strength, contact time, reaction temperature as well as radionuclide preliminary concentrations with the use of the batch methodology. As revealed by the findings, the sorption of radionuclides on CNF/LDH nanocomposite adhered to the pseudo-second-order kinetic model as well as Langmuir model. The maximum elimination capacity of U(VI) amounted to be 0.7 mmol/g. The independent of ionic strength shed light on the fact that inner-sphere surface complexation mainly overpowered radionuclide uptake by the CNF/LDH nanocomposite, which was further verified through the combination of FTIR and XPS spectral analyses. The abovementioned analyses shed light on the fact that the CNF/LDH nanocomposite can be regarded as a latent material to preconcentration radionuclides for environmental remediation.

scholarly journals Study on the adsorption of methylene blue from aqueous solution using hydrogel glucomannan/graphene oxide

2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Graphene Oxide ◽  
Adsorption Capacity ◽  
Organic Dyes ◽  
Dye Adsorption ◽  
Order Kinetic ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.

scholarly journals Karekterisasi, Kinetika, dan Isoterm Adsorpsi Limbah Ampas Kelapa sebagai Adsorben Ion Cu(II)

SAINTIFIK ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 104-115
Author(s):  
Agusriyadin Agusriyadin
Keyword(s):  
Adsorption Capacity ◽  
Ph Effect ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Optimum Conditions ◽  
Langmuir Adsorption ◽  
Adsorbent Surface ◽  
Adsorption Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Penelitian ini bertujuan untuk menguji kemampuan AK dan AKPM dalam mengadsorpsi ion Cu (II), pengaruh parameter adsorpsi dan mekanisme adsorpsi. AK dan AKP Madsorben dibuat dari residu ampas kelapa. Adsorben dikarakterisasi dengan FTIR, SEM dan EDS. Pengaruh parameter adsorpsi seperti pH awal, dosis adsorben, waktu kontak dan konsentrasi ion Cu (II) awal diperiksa untuk menentukan kondisi optimum serapan tembaga (II). Ion Cu (II) yang teradsorpsi diukur berdasarkan pada konsentrasi Ion Cu (II) sebelum dan sesudah adsorpsi menggunakan metode AAS. Hasil karakterisasi menunjukkan bahwa struktur pori dan gugus fungsi tersedia pada permukaan adsorben. Menurut percobaan efek pH, kapasitas adsorpsi maksimum dicapai pada pH 7. Waktu kontak optimal dan konsentrasi tembaga awal (II) ditemukan masing-masing pada 120 menit dan 100 mg L-1. Data eksperimental sesuai dengan model kinetik orde dua orde dua, dan Langmuir isoterm adsorpsi yang diperoleh paling sesuai dengan data adsorpsi. Kapasitas adsorpsi maksimum adsorben ditemukan menjadi 4,73 dan 6,46 mg g-1 pada kondisi optimal. The results of characterization showed that the pore structure and the functional groups were available on adsorbent surface. According to the pH effect experiments, the maximum adsorption capacity was achieved at pH 7. Optimum contact time and initial copper(II) concentration were found at 120 min and 100 mg L-1, respectively. The experimental data were comply with the pseudo-second-order kinetic model, and Langmuir adsorption isotherm obtained best fitted the adsorption data. The maximum adsorption capacity of the adsorbents was found to be 4.73 and 6.46 mg g-1 at optimum conditions.

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

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.

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 Preparation of grafting copolymer of acrylic acid onto loess surface and its adsorption behavior

2020 ◽  
Vol 82 (4) ◽  
pp. 673-682
Author(s):  
Fengqin Tang ◽  
Di Gao ◽  
Li Wang ◽  
Yufeng He ◽  
Pengfei Song ◽  
...  
Keyword(s):  
Acrylic Acid ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Vinyl Pyrrolidone ◽  
Mineral Particle ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Order Kinetic Model ◽  
Grafting Copolymer

Abstract Loess is a typical natural mineral particle distributed widely around the world, and it is inexpensive, readily accessible, and harmless to the environment. In this study, loess was modified by surface grafting copolymerization of functional monomers, such as acrylic acid, N-vinyl pyrrolidone, and N,N-methylenebisacrylamide as a cross-linking agent, which afforded a novel loess-based grafting copolymer (LC-PAVP). After being characterized by scanning electron microscopy, thermal gravimetric analysis and Fourier-transform infrared spectroscopy, its adsorption capacity and mechanism of removing lead ions (Pb2+) were investigated. With the study of the optimal experimental conditions, it was demonstrated that the removal rate of Pb2+ by LC-PAVP can reach up to 99.49% in 60 min at room temperature. It was also found that the kinetic characteristics of the adsorption capacity due to the pseudo-second-order kinetic model and the thermodynamics conformed well with the Freundlich model. In summary, as a lost-cost and eco-friendly loess-based adsorbent, LC-PAVP is a good potential material for wastewater treatment.

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