scholarly journals Cr (III) Removal Capacity in Aqueous Solution in Relation to the Functional Groups Present in the Orange Peel (Citrus sinensis)

2021 ◽  
Vol 11 (14) ◽  
pp. 6346
Author(s):  
Laura Patiño-Saldivar ◽  
José A. Hernández ◽  
Alba Ardila ◽  
Mercedes Salazar-Hernández ◽  
Alfonso Talavera ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Functional Groups ◽  
Orange Peel ◽  
Pollutant Removal ◽  
External Mass Transfer ◽  
Equilibrium Studies ◽  
Removal Capacity ◽  
Point Analysis ◽  
Agroindustrial Waste ◽  
Previously Treated

Bioremediation is a pollutant removal method that has had a great boom due to the diversity of agroindustrial waste that can be used for this purpose, and that has shown having great efficiency and profitability in the adsorption of heavy metals, such as Pb, Cu, and Co. Based on the above, the present work carried out kinetic and equilibrium studies of bioadsorption of Cr (III) using orange peel (OP) as adsorbent, previously treated with methanol, water, and a water–methanol mixture at different pH (0.91, 1.78 and 2.72), and at 30 °C, finding that the adsorption capacity at equilibrium increases with increasing pH, having a maximum of 55 mg g−1 at pH 2.72—under these conditions, lower adsorption energy was used to remove Cr (III). In addition, it was determined that there are no external mass transfer limitations. An isoelectric point analysis indicated that the adsorption is not carried out by electrostatic forces and a FTIR study of the functional groups of OP showed a decrease in the main functional groups (pectin, cellulose, and lignin, among others), which is directly related to the adsorption capacity of the bioadsorbent.

scholarly journals Synthesis of Porous Boron-Doped Carbon Nitride: Adsorption Capacity and Photo-Regeneration Properties

2019 ◽  
Vol 16 (4) ◽  
pp. 581 ◽  
Author(s):  
Xiang Guo ◽  
Lei Rao ◽  
Peifang Wang ◽  
Lixin Zhang ◽  
Yuxiong Wang
Keyword(s):  
Adsorption Capacity ◽  
Carbon Nitride ◽  
Adsorption Process ◽  
Pollutant Removal ◽  
Practical Applications ◽  
Removal Capacity ◽  
Boron Doped ◽  
Powder Suspension ◽  
Photocatalytic Concrete ◽  
Excellent Stability

Carbon nitride (CN) with improved adsorption–degradation capacity was synthesized using B2O3 and CN via calcination. The pollutant removal capacity of this B2O3/CN (B-CN) was studied by a powder suspension experiment and added into concrete to evaluate the adsorption and degradation of methylene blue (MB). The characterizations of all samples indicate that B2O3 significantly affects CN, e.g., by increasing the CN specific surface area to 3.6 times the original value, extending visible light adsorption, and narrowing the band gap from 2.56 eV to 2.42 eV. Furthermore, the results show that B-CN composite materials have a higher MB-removal efficiency, with the adsorption capacity reaching 43.11 mg/g, which is about 3.3 times that of pristine CN. The MB adsorption process on B2-CN is mainly via electrostatic attraction and π–π interactions. In addition, B-CN added into concrete also has good performance. After five adsorption–degradation cycles, B-CN and photocatalytic concrete still exhibit a good regenerate ability and excellent stability, which are very important for practical applications.

scholarly journals Study on the Uptake of Aqueous Zinc Ion Onto a Novel Organic Acid Modified Biosorbent

2021 ◽  
Author(s):  
Chukwunonso O. Aniagor ◽  
D. M. Hussein ◽  
S. Farag ◽  
Ali Hashem
Keyword(s):  
Adsorption Capacity ◽  
Functional Groups ◽  
Metal Binding ◽  
Invasive Plant ◽  
Interaction Mechanism ◽  
Zinc Ion ◽  
Maximum Adsorption Capacity ◽  
Acceptor Interaction ◽  
Equilibrium Studies ◽  
Carboxyl Content

Abstract Alhagi Graecorum (AG) is an invasive plant with a massive/robust root structure that can grow up to 12 feet into the ground. The present study exploited the rich cellulosic content in this ‘AG’ root for the synthesis of a novel biosorbent (‘MA’). This low-cost biosorbent, with high carboxyl content of 447.22 (m. eq /100 g sample) was utilised for aqueous zinc ion sequestration. The surface functional groups and textural characteristics required for an efficient heavy metal binding was identified on ‘MA’ using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Sip isotherm emerged as the model of best fit for equilibrium studies, hence, Zn (II) ion sorption onto ‘MA’ is believed to occur via a hybrid blend of homogenous monolayer and heterogeneous multilayer adsorption. Meanwhile, the Elovich (SNE = 1.0429), intraparticle diffusion (SNE = 1.0205) and pseudo-first-order (SNE = 1.0455) provided the best fitting for 200, 400 and 600 mg/L adsorption system, respectively. The maximum adsorption capacity of 188.67 mg/g was recorded at optimum adsorption conditions, with the predominance of the electrostatic and electron-donor-acceptor interaction mechanism. The abundant surface oxygenous functional groups on ‘MA’ positively influenced its adsorption capacity; thus, making it a promising biosorbent for aqueous Zn (II) uptake.

Ouricuri (Syagrus coronata) fiber: a novel biosorbent to remove methylene blue from aqueous solutions

2016 ◽  
Vol 75 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Lucas Meili ◽  
Társila Santos da Silva ◽  
Daniely Carlos Henrique ◽  
João Inácio Soletti ◽  
Sandra Helena Vieira de Carvalho ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Experimental Design ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Fiber Diameter ◽  
Aqueous Media ◽  
Process Efficiency ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Studies

In this work, the potential of ouricuri (Syagrus coronata) fiber as a novel biosorbent to remove methylene blue (MB) from aqueous solutions was investigated. The fiber was prepared and characterized according to the fundamental features for adsorption. A 23 experimental design was used to evaluate the effects of adsorbent dosage (M), fiber diameter (D) and agitation (A) on the adsorption capacity. In the more adequate conditions, kinetic and equilibrium studies were performed. The experimental design results showed that M = 10 g L−1), D = 0.595 mm and A = 200 rpm were the more adequate conditions for MB adsorption. Based on the kinetic study, it was found that the adsorption process was fast, being the equilibrium was attained at about 5 min, with 90% of color removal. The isotherm was properly represented by the Sips model, and the maximum adsorption capacity was 31.7 mg g−1. In brief, it was demonstrated that ouricuri fiber is an alternative biosorbent to remove MB from aqueous media, taking into account the process efficiency and economic viewpoint.

scholarly journals Exploratory study to assess the impact of chitosan /bentonite ratio on the metal removal capacity of chitosan modified bentonite clay

2016 ◽  
Vol 18 (2) ◽  
pp. 437-443 ◽  
Keyword(s):  
Physical Properties ◽  
Adsorption Capacity ◽  
Adsorption Isotherms ◽  
Exploratory Study ◽  
Metal Removal ◽  
Bentonite Clay ◽  
Settling Rate ◽  
Modified Bentonite ◽  
Removal Capacity ◽  
The Impact

<div> <p>Adsorption is one of the methods that can be used for metal removal. In this study five metals were used cadmium, chromium, lead, copper and Nickel (Cd, Cr, Pb, Cu, and Ni) over a concentration range from 0.8 to about 7 mg l<sup>-1</sup> for each metal. Adsorbents were prepared with increasing chitosan to bentonite ratio from 0 to 0.67 g chitosan/g bentonite. The study showed that adsorption of metals on plain bentonite and chitosan modified bentonite can fit well with Langmuir and Freundlich adsorption isotherms. Furthermore, the bentonite adsorption capacity will decrease with the increase of chitosan/bentonite ratio. This study concluded that bentonite is a good adsorbent. However, the applicability of bentonite as potential adsorbent may be limited by its physical properties such as slow settling rate and difficulty to use it as an adsorbent in adsorption columns. Despite the decrease of maximum theoretical adsorption capacity as a result of chitosan modification, the addition of small amount of chitosan can improve the physical characteristics of bentonite clay to be used as an adsorbent.&nbsp;</p> </div> <p>&nbsp;</p>

scholarly journals Effect of synthesis conditions  on  methylene blue adsorption capacity of electrochemically preparated graphene

2020 ◽  
Vol 9 (3) ◽  
pp. 9-14
Author(s):  
Hao Pham Van ◽  
Linh Ha Xuan ◽  
Oanh Phung Thi ◽  
Hong Phan Ngoc ◽  
Huy Nguyen Nhat ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Graphene Nanosheets ◽  
Electrochemical Exfoliation ◽  
X Ray ◽  
Synthesis Conditions ◽  
Mb Adsorption

This report presents the effect of synthesis conditions on the synthesis of graphene nanosheets via electrochemical exfoliation method for adsorbing methylene blue from aqueous solution. Oxygen-containing functional groups and defects in the material were characterized by Raman and X-ray photoelectron spectroscopy (XPS). As a result, by using voltage of 15 V, (NH4)2SO4 (5%, 250 mL) and KOH (7.5%, 250 mL), the obtained material showed the highest MB adsorption capacity due to the high densities of oxygen-containing groups and defects comparison to other conditions.

An Environmentally Friendly Technology for Biomass Production Hydorchar from Renewable Resources

2013 ◽  
Vol 726-731 ◽  
pp. 634-637 ◽  
Author(s):  
Yan Qiu Lei ◽  
Hai Quan Su
Keyword(s):  
Activated Carbon ◽  
Reaction Time ◽  
Adsorption Capacity ◽  
Functional Groups ◽  
Biomass Production ◽  
Renewable Resources ◽  
Environmentally Friendly ◽  
Hydrothermal Carbonization ◽  
Removal Rates

A green and sustainable route for preparation of hydrochars from cornstalk by hydrothermal carbonization (200°C) was described. The morphology of the hydrochars changed with reaction time increased, the surface of the materials contained a large number of functional groups, showed higher adsorption capacity for Cr (VI) than activated carbon and the removal rates of Cr (VI) were 67% and 29% respectively (pH=1, 20°C).

scholarly journals Equilibrium and Kinetic Study of Lead and Copper Ion Adsorption on Chitosan-Grafted-Polyacrylic Acid Synthesized by Surface Initiated Atomic Transfer Polymerization

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2218 ◽  
Author(s):  
Carlos Grande-Tovar ◽  
William Vallejo ◽  
Fabio Zuluaga
Keyword(s):  
Adsorption Capacity ◽  
Polyacrylic Acid ◽  
Adsorption Process ◽  
Kinetic Constant ◽  
Copper Ion ◽  
Toxic Metal ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Equilibrium Studies ◽  
Pseudo Second Order

In this work, we synthesized chitosan grafted-polyacrylic acid (CS-g-PA) through surface-initiated atom transfer radical polymerization (SI-ATRP). We also studied the adsorption process of copper and lead ions onto the CS-g-PA surface. Adsorption equilibrium studies indicated that pH 4.0 was the best pH for the adsorption process and the maximum adsorption capacity over CS-g-PA for Pb2+ ions was 98 mg·g−1 and for Cu2+ it was 164 mg·g−1, while for chitosan alone (CS), the Pb2+ adsorption capacity was only 14.8 mg·g−1 and for Cu2+ it was 140 mg·g−1. Furthermore, the adsorption studies indicated that Langmuir model describes all the experimental data and besides, pseudo-second-order model was suitable to describe kinetic results for the adsorption process, demonstrating a larger kinetic constant of the process was larger for Pb2+ than Cu2+. Compared to other adsorbents reported, CS-g-PA had comparable or even superior adsorbent capacity and besides, all these results suggest that the new CS-g-PA polymers had potential as an adsorbent for hazardous and toxic metal ions produced by different industries.

scholarly journals Biochar from Agricultural by-Products for the Removal of Lead and Cadmium from Drinking Water

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2933
Author(s):  
Edgar Pineda Puglla ◽  
Diana Guaya ◽  
Cristhian Tituana ◽  
Francisco Osorio ◽  
María J. García-Ruiz
Keyword(s):  
Drinking Water ◽  
Adsorption Capacity ◽  
Freundlich Isotherm ◽  
Maximum Adsorption Capacity ◽  
Peanut Shell ◽  
Experimental Conditions ◽  
Lower Efficiency ◽  
Lead And Cadmium ◽  
Removal Capacity ◽  
Removal Of Heavy Metals

This study reports the adsorption capacity of lead Pb2+ and cadmium Cd2+ of biochar obtained from: peanut shell (BCM), “chonta” pulp (BCH) and corn cob (BZM) calcined at 500, 600 and 700 °C, respectively. The optimal adsorbent dose, pH, maximum adsorption capacity and adsorption kinetics were evaluated. The biochar with the highest Pb2+ and Cd2+ removal capacity is obtained from the peanut shell (BCM) calcined at 565 °C in 45 min. The optimal experimental conditions were: 14 g L−1 (dose of sorbent) and pH between 5 and 7. The sorption experimental data were best fitted to the Freundlich isotherm model. High removal rates were obtained: 95.96% for Pb2+ and 99.05. for Cd2+. The BCH and BZM revealed lower efficiency of Pb2+ and Cd2+ removal than BCM biochar. The results suggest that biochar may be useful for the removal of heavy metals (Pb2+ and Cd2+) from drinking water.

scholarly journals Removal of Cu(II) from Aqueous Solutions Using Amine-Doped Polyacrylonitrile Fibers

2020 ◽  
Vol 10 (5) ◽  
pp. 1738
Author(s):  
Kay Thwe Aung ◽  
Seung-Hee Hong ◽  
Seong-Jik Park ◽  
Chang-Gu Lee
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Equilibrium Studies ◽  
Naoh Solution ◽  
Surface Modified ◽  
Pan Fibers

Polyacrylonitrile (PAN) fibers were prepared via electrospinning and were modified with diethylenetriamine (DETA) to fabricate surface-modified PAN fibers. The surface-modified PAN fibers were used to evaluate their adsorption capacity for the removal of Cu(II) from aqueous solutions. Batch adsorption experiments were performed to examine the effects of the modification process, initial concentration, initial pH, and adsorbent dose on the adsorption of Cu(II). Kinetic analysis revealed that the experimental data fitted the pseudo-second-order kinetic model better than the pseudo-first-order model. Adsorption equilibrium studies were conducted using the Freundlich and Langmuir isotherm models, and the findings indicated that the PAN fibers modified with 85% DETA presented the highest adsorption capacity for Cu(II) of all analyzed samples. Moreover, the results revealed that the Freundlich model was more appropriate than the Langmuir one for describing the adsorption of Cu(II) onto the modified fibers at various initial Cu(II) concentrations. The maximum adsorption capacity was determined to be 87.77 mg/g at pH 4, and the percent removal of Cu(II) increased as the amount of adsorbent increased. Furthermore, the surface-modified PAN fibers could be easily regenerated using NaOH solution. Therefore, surface-modified PAN fibers could be used as adsorbents for the removal of Cu(II) from aqueous solutions.

scholarly journals CVD Synthesis, Functionalization and CO2 Adsorption Attributes of Multiwalled Carbon Nanotubes

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 634 ◽  
Author(s):  
Shazia Shukrullah ◽  
Muhammad Yasin Naz ◽  
Norani M. Mohamed ◽  
Khalid A. Ibrahim ◽  
Nasser M. AbdEl-Salam ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Adsorption Capacity ◽  
Multiwalled Carbon Nanotubes ◽  
Functional Groups ◽  
Co2 Adsorption ◽  
Breakthrough Curves ◽  
Multiwalled Carbon ◽  
Amine Functionalized ◽  
Co2 Adsorption Capacity

Carbon dioxide is one of the major greenhouse gases and a leading source of global warming. Several adsorbent materials are being tested for removal of carbon dioxide (CO2) from the atmosphere. The use of multiwalled carbon nanotubes (MWCNTs) as a CO2 adsorbent material is a relatively new research avenue. In this study, Fe2O3/Al2O3 composite catalyst was used to synthesize MWCNTs by cracking ethylene gas molecules in a fluidized bed chemical vapor deposition (CVD) chamber. These nanotubes were treated with H2SO4/HNO3 solution and functionalized with 3-aminopropyl-triethoxysilane (APTS). Chemical modification of nanotubes removed the endcaps and introduced some functional groups along the sidewalls at defected sites. The functionalization of nanotubes with amine introduced carboxylic groups on the tube surface. These functional groups significantly enhance the surface wettability, hydrophilicity and CO2 adsorption capacity of MWCNTs. The CO2 adsorption capacity of as-grown and amine-functionalized CNTs was computed by generating their breakthrough curves. BELSORP-mini equipment was used to generate CO2 breakthrough curves. The oxidation and functionalization of MWCNTs revealed significant improvement in their adsorption capacity. The highest CO2 adsorption of 129 cm3/g was achieved with amine-functionalized MWCNTs among all the tested samples.

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