Recycling agriculture wastes of ramie stalk as bioadsorbents for Cd2+ removal: a kinetic and thermodynamic study

2015 ◽  
Vol 73 (2) ◽  
pp. 396-404 ◽  
Author(s):  
S. Xu ◽  
X. F. Gong ◽  
H. L. Zou ◽  
C. Y. Liu ◽  
C. L. Chen ◽  
...  
Keyword(s):  
Metal Removal ◽  
Lignin Content ◽  
Heavy Metal Removal ◽  
Complexation Reaction ◽  
Order Kinetic ◽  
Inhomogeneous Surface ◽  
Adsorption Sites ◽  
Ramie Stalk ◽  
Agriculture Wastes ◽  
High Cellulose

In this study, we exhibit the recycling of agriculture wastes of ramie stalk as bioadsorbents for Cd2+ removal. Based on our experimental results, it is realized that Cd2+ adsorption to ramie stalk is highly pH sensitive, indicating the adsorption is driven by surface complexation reaction. The high adsorption capacity of ramie stalk toward Cd2+ (qm = 10.33 mg g−1, 0.09 mol-Cd g−1), which corresponds to around 21.95% of active adsorption sites available of ramie stalk, is believed to be closely related to its high cellulose and lignin content. The inhomogeneous surface of ramie stalk due to the high cellulose and lignin content also accounts for the observation that the adsorption kinetic is described well by the pseudo second order kinetic model. Results from thermodynamic studies suggest that the adsorption process is endothermic and spontaneous. All these properties demonstrate the potential of ramie stalk as a low cost bioadsorbent for the application of heavy metal removal.

scholarly journals Cd(II) and Pb(II) Adsorption Using a Composite Obtained from Moringa oleifera Lam. Cellulose Nanofibrils Impregnated with Iron Nanoparticles

Water ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 89
Author(s):  
Adriana Vázquez-Guerrero ◽  
Raúl Cortés-Martínez ◽  
Ruth Alfaro-Cuevas-Villanueva ◽  
Eric M. Rivera-Muñoz ◽  
Rafael Huirache-Acuña
Keyword(s):  
Moringa Oleifera ◽  
Iron Nanoparticles ◽  
Metal Removal ◽  
Cellulose Nanofibers ◽  
Cellulose Nanofibrils ◽  
Heavy Metal Removal ◽  
Order Kinetic ◽  
Adsorption Method ◽  
Adsorption Capacities ◽  
Moringa Oleifera Lam

This work informs on the green synthesis of a novel adsorbent and its adsorption capacity. The adsorbent was synthesized by the combination of iron nanoparticles and cellulose nanofibers (FeNPs/NFCs). Cellulose nanofibers (NFCs) were obtained from Moringa (Moringa oleifera Lam.) by a pulping Kraft process, acid hydrolysis, and ultrasonic methods. The adsorption method has advantages such as high heavy metal removal in water treatment. Therefore, cadmium (Cd) and lead (Pb) adsorption with FeNP/NFC from aqueous solutions in batch systems was investigated. The kinetic, isotherm, and thermodynamic parameters, as well as the adsorption capacities of FeNP/NFC in each system at different temperatures, were evaluated. The adsorption kinetic data were fitted to mathematical models, so the pseudo-second-order kinetic model described both Cd and Pb. The kinetic rate constant (K2), was higher for Cd than for Pb, indicating that the metal adsorption was very fast. The adsorption isotherm data were best described by the Langmuir–Freundlich model for Pb multilayer adsorption. The Langmuir model described Cd monolayer sorption. However, experimental maximum adsorption capacities (qe exp) for Cd (>12 mg/g) were lower than those for Pb (>80 mg/g). In conclusion, iron nanoparticles on the FeNP/NFC composite improved Cd and Pb selectivity during adsorption processes, indicating the process’ spontaneous and exothermic nature.

scholarly journals Novel NS Modified Cellulose: Synthesis, Spectroscopic Characterization and Adsorption Studies of Cu2+, Hg2+ and Pb2+ From Environmental Water Samples

2021 ◽  
Author(s):  
Magda Akl ◽  
Mohamed A. Ismail ◽  
Mohamed A. Hashem ◽  
Dina A. Ali
Keyword(s):  
Water Samples ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Spectroscopic Characterization ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Phenyl Isothiocyanate ◽  
Cellulose Synthesis ◽  
Order Kinetic ◽  
Modified Cellulose

Abstract In this work, an attempt was made to modify natural cellulose powder via three steps process; oxidation by potassium periodate followed by condensation with aminoguanidine and eventually reaction with phenyl isothiocyanate. The modified cellulose (PhGu-MC) was characterized by several techniques including Fourier transform infrared spectra (FTIR), scanning electron microscope (SEM), and elemental analysis (EA), Brunauer–Emmett–Teller analysis (BET) and thermogravimetric analysis (TGA). The modified cellulose (PhGu-MC) was used as an adsorbent for Cu2+, Hg2+ and Pb2+ from aqueous solution and environmental water samples. Effects of various factors on the adsorption efficiency were investigated including pH, initial metal concentration, contact time, adsorbent dose, temperature and interfering ions on adsorption was investigated to estimate the optimum adsorption conditions. At optimum adsorption conditions, the adsorption capacities of Cu2+, Hg2+ and Pb2+ were found to be 50, 94 and 55 mg.g−1, respectively. The adsorption process was, well described by the Langmuir model, and it was found to follow the pseudo-second-order kinetic model. The synthesized (PhGu-MC) has revealed significant potential towards heavy metal removal from environmental water samples.

scholarly journals Studies on the Removal of Cadmium Toxic Metal Ions by Natural Clays from Aqueous Solution by Adsorption Process

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Rajaa Bassam ◽  
Achraf El hallaoui ◽  
Marouane El Alouani ◽  
Maissara Jabrane ◽  
El Hassan El Khattabi ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Process ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Toxic Metal ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Solution Ph ◽  
Natural Clays

The aim of this study is the valorization of the Moroccan clays (QC-MC and QC-MT) from the Middle Atlas region as adsorbents for the treatment of water contaminated by cadmium Cd (II) ions. The physicochemical properties of natural clays are characterized by ICP-MS, XRD, FTIR, and SEM techniques. The adsorption process is investigated as a function of adsorbent mass, solution pH, contact time, temperature, and initial Cd (II) ion concentration. The kinetic investigation shows that the adsorption equilibrium of Cd (II) ions by both natural clays is reached after 30 min for QC-MT and 45 min for QC-MC and fits well to a pseudo-second-order kinetic model. The isotherm study is best fitted by a Freundlich model, with the maximum adsorption capacity determined by the linear form of the Freundlich isotherm being 4.23 mg/g for QC-MC and 5.85 mg/g for QC-MT at 25°C. The cadmium adsorption process was thermodynamically spontaneous and exothermic. The regeneration process showed that these natural clays had excellent recycling capacity. Characterization of the Moroccan natural clays before and after the adsorption process through FTIR, SEM, XRD, and EDX techniques confirmed the Cd (II) ion adsorption on the surfaces of both natural clay adsorbents. Overall, the high adsorption capacity of both natural clays for Cd (II) ions removal compared to other adsorbents motioned in the literature indicated that these two natural adsorbents are excellent candidates for heavy metal removal from aqueous environments.

Aluminosilicate-based adsorbent in equimolar and non-equimolar binary-component heavy metal removal systems

2015 ◽  
Vol 72 (12) ◽  
pp. 2166-2178 ◽  
Author(s):  
Meng Xu ◽  
Pejman Hadi ◽  
Chao Ning ◽  
John Barford ◽  
Kyoung Jin An ◽  
...  
Keyword(s):  
Metal Ion ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Threshold Value ◽  
Industrial Applications ◽  
Molar Ratio ◽  
Toxic Heavy Metals ◽  
Component System ◽  
Molar Ratios ◽  
Adsorption Sites

Cadmium (Cd) and lead (Pb) are toxic heavy metals commonly used in various industries. The simultaneous presence of these metals in wastewater amplifies the toxicity of wastewater and the complexity of the treatment process. This study has investigated the selective behavior of an aluminosilicate-based mesoporous adsorbent. It has been demonstrated that when equimolar quantities of the metals are present in wastewater, the adsorbent uptakes the Pb2+ ions selectively. This has been attributed to the higher electronegativity value of Pb2+ compared to Cd2+ which can be more readily adsorbed on the adsorbent surface, displacing the Cd2+ ions. The selectivity can be advantageous when the objective is the separation and reuse of the metals besides wastewater treatment. In non-equimolar solutions, a complete selectivity can be observed up to a threshold Pb2+ molar ratio of 30%. Below this threshold value, the Cd2+ and Pb2+ ions are uptaken simultaneously due to the abundance of Cd2+ ions and the availability of adsorption sites at very low Pb2+ molar ratios. Moreover, the total adsorption capacities of the adsorbent for the multi-component system have been shown to be in the same range as the single-component system for each metal ion which can be of high value for industrial applications.

scholarly journals Enhanced Heavy Metal Removal from Acid Mine Drainage Wastewater Using Double-Oxidized Multiwalled Carbon Nanotubes

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 111 ◽  
Author(s):  
Carolina Rodríguez ◽  
Eduardo Leiva
Keyword(s):  
Heavy Metals ◽  
Carbon Nanotubes ◽  
Heavy Metal ◽  
Multiwalled Carbon Nanotubes ◽  
Sorption Capacity ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Order Kinetic ◽  
Multiwalled Carbon ◽  
Oxidized Multiwalled Carbon Nanotubes

Due to the unique properties of carbon nanotubes (CNTs), they have attracted great research attention as an emergent technology in many applications including water and wastewater treatment. However, raw CNTs have few functional groups, which limits their use in heavy metal removal. Nevertheless, their removal properties can be improved by oxidation processes that modify its surface. In this study, we assessed the capacity of oxidized and double-oxidized multiwalled carbon nanotubes (MWCNTs) to remove heavy metals ions from acidic solutions. The MWCNTs were tested for copper (Cu), manganese (Mn), and zinc (Zn) removal, which showed an increment of 79%, 78%, and 48%, respectively, with double-oxidized MWCNTs compared to oxidized MWCNTs. Moreover, the increase in pH improved the sorption capacity for all the tested metals, which indicates that the sorption potential is strongly dependent on the pH. The kinetic adsorption process for three metals can be described well with a pseudo-second-order kinetic model. Additionally, in multimetallic waters, the sorption capacity decreases due to the competition between metals, and it was more evident in the removal of Zn, while Cu was less affected. Besides, XPS analysis showed an increase in oxygen-containing groups on the MWCNTs surface after oxidation. Finally, these analyses showed that the chemical interactions between heavy metals and oxygen-containing groups are the main removal mechanism. Overall, these results contribute to a better understanding of the potential use of CNTs for water treatment.

scholarly journals Adsorption of Ni2+ and Cd2+ from Water by Calcium Alginate/Spent Coffee Grounds Composite Beads

2019 ◽  
Vol 9 (21) ◽  
pp. 4531 ◽  
Author(s):  
Roberto Torres-Caban ◽  
Carmen A. Vega-Olivencia ◽  
Nairmen Mina-Camilde
Keyword(s):  
Heavy Metals ◽  
Calcium Alginate ◽  
Metal Removal ◽  
Low Cost ◽  
Heavy Metal Removal ◽  
Point Of Zero Charge ◽  
Order Kinetic ◽  
Spent Coffee Grounds ◽  
Composite Beads ◽  
Coffee Grounds

The use of heavy metals in technological applications has led to detrimental effects on human health and the environment. Activated carbon and ion-exchange resins are commonly used to remove pollutants but they are expensive. Therefore, the research of low-cost alternatives derived from natural resources and organic wastes is being considered. The aim of this study considers the use of Calcium Alginate/Spent Coffee Grounds (CA–SCGs) composite beads to adsorb heavy metals from aqueous solutions, particularly, the removal of Ni2+ or Cd2+ at concentrations from 10 ppm to 100 ppm. CA–SCGs beads were made of equal proportions of alginate and spent coffee grounds and compared with calcium alginate beads (CA beads) and spent coffee grounds (SCGs) in terms of capacity and rate of adsorption. Three cycles of adsorption/desorption were done. The beads were characterized by Scanning Electron Microscopy coupled with an energy-dispersive X-ray spectroscopy (SEM–EDX), Fourier-transform infrared spectroscopy (FT–IR), Raman spectroscopy, and point of zero charge. Langmuir, Freundlich, and Sips models, and a pseudo-second-order kinetic equation were used. Sips model showed the best correlation with the adsorption of CA–SCGs beads with capacities of adsorption of 91.18 mg/g for cadmium and 20.96 mg/g for nickel. CA–SCGs beads had a greater adsorption than the CA beads, achieving adsorption percentages close to 100% than alginate alone, showing their effectiveness in heavy metal removal.

scholarly journals Removal of Cadmium and Lead from Aqueous Solution by Hydroxyapatite/Chitosan Hybrid Fibrous Sorbent: Kinetics and Equilibrium Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Soyeon Park ◽  
Allan Gomez-Flores ◽  
Yong Sik Chung ◽  
Hyunjung Kim
Keyword(s):  
Heavy Metal ◽  
Metal Ion ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Chitosan Solution ◽  
Phosphoric Acid Solution ◽  
Order Kinetic ◽  
Hybrid Fiber ◽  
Hybrid Fibers ◽  
Equilibrium Studies

Hydroxyapatite (HAp)/chitosan composites were prepared by a coprecipitation method, dropping a mixture of chitosan solution and phosphoric acid solution into a calcium hydroxide solution. Using the HAp/chitosan composites prepared, HAp/chitosan hybrid fibers with various HAp contents were prepared by a wet spinning method. X-ray diffraction and scanning electron microscopy analyses revealed that HAp particles were coated onto the surface of the fiber, and the surface roughness increased with increasing the HAp contents in the fiber. In order to evaluate the heavy metal removal characteristics of the HAp/chitosan hybrid fiber, adsorption tests were conducted and the results were compared with those of bare chitosan fibers. The results showed better performance in heavy metal ion removal for the HAp/chitosan hybrid fiber than the chitosan fiber. As the HAp content in the hybrid fiber increased, the removal efficiency of heavy metal ions also increased due to the increase of the specific surface area of the HAp/chitosan hybrid fiber. Adsorption kinetic and isotherm tests revealed that Pb2+and Cd2+adsorption to the hybrid fiber follows pseudo-second-order kinetic and Langmuir-type adsorption, respectively.

scholarly journals Removal of Zn(II), Mn(II) and Cu(II) by adsorption onto banana stalk biochar: adsorption process and mechanisms

2020 ◽  
Vol 82 (12) ◽  
pp. 2962-2974
Author(s):  
Hua Deng ◽  
Qiuyan Li ◽  
Meijia Huang ◽  
Anyu Li ◽  
Junyu Zhang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Photoelectron Spectroscopy ◽  
Heavy Metal Ions ◽  
Metal Removal ◽  
Low Cost ◽  
Heavy Metal Removal ◽  
Order Kinetic ◽  
Solution Ph ◽  
X Ray

Abstract Low-cost banana stalk (Musa nana Lour.) biochar was prepared using oxygen-limited pyrolysis (at 500 °C and used), to remove heavy metal ions (including Zn(II), Mn(II) and Cu(II)) from aqueous solution. Adsorption experiments showed that the initial solution pH affected the ability of the biochar to adsorb heavy metal ions in single- and polymetal systems. Compared to Mn(II) and Zn(II), the biochar exhibited highly selective Cu(II) adsorption. The adsorption kinetics of all three metal ions followed the pseudo-second-order kinetic equation. The isotherm data demonstrated the Langmuir model fit for Zn(II), Mn(II) and Cu(II). The results showed that the chemical adsorption of single molecules was the main heavy metal removal mechanism. The maximum adsorption capacities (mg·g−1) were ranked as Cu(II) (134.88) > Mn(II) (109.10) > Zn(II) (108.10)) by the single-metal adsorption isotherms at 298 K. Moreover, characterization analysis was performed using Fourier transform infrared spectroscopy, the Brunauer-Emmett-Teller method, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results revealed that ion exchange was likely crucial in Mn(II) and Zn(II) removal, while C-O, O-H and C = O possibly were key to Cu(II) removal by complexing or other reactions.

Characteristics and adsorption properties of iron-coated sand

1997 ◽  
Vol 35 (7) ◽  
pp. 63-70 ◽  
Author(s):  
Shang-Lien Lo ◽  
Hung-Te Jeng ◽  
Chin-Hsing Lai
Keyword(s):  
Heavy Metals ◽  
Iron Oxide ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Acid Resistance ◽  
Batch Adsorption ◽  
X Ray ◽  
Adsorption Sites ◽  
Coated Layer ◽  
Coated Sand

This study was conducted to develop a process for coating hydrated iron oxide on the surface of quartz sand to utilize the adsorbent properties of the coating and the filtration properties of the sand. Three coating parameters were investigated: pH, Fe concentration at which iron oxide was prepared, and the coating temperature. A Scanning Electron Microscope (SEM) and X-Ray Diffractometer (XRD) were used to observe the surface properties of the coated layer. Acid resistance was used to evaluate the attachment strength of the coated layer. Batch adsorption tests were performed to compare the effects of each coating parameter on the adsorption of heavy metals on the coated layer. Energy Dispersive Analysis of X-ray (EDAX) was used for characterizing metal adsorption sites on the iron-coated sand. The results indicated that the coated sand had more pores and higher specific surface area because of the attachment of iron oxide. The coated sand produced at higher pH(coating) had better adsorption efficiencies of metals but had worse acid resistance. A high-temperature coating process enhanced the stability of the oxide coatings. Comparing heavy metal removal by adsorption on iron-coated sand and chemical precipitation, adsorption was shown to be capable of removing heavy metals over a wider pH range and to much lower levels than precipitation. The results from EDAX analysis showed that copper ions were chemisorbed on the surface of iron-coated sand.

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