scholarly journals Adsorption Mechanisms and Characteristics of Hg2+ Removal by Different Fractions of Biochar

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2105
Author(s):  
Xiaoli Guo ◽  
Menghong Li ◽  
Aijv Liu ◽  
Man Jiang ◽  
Xiaoyin Niu ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Raw Material ◽  
Mercury Contamination ◽  
Main Reaction ◽  
Hydroxyl Groups ◽  
Complexation Reaction ◽  
X Ray ◽  
Adsorption Mechanisms

The adsorption mechanisms of mercury ion (Hg2+) by different fractions of biochar were studied, providing a theoretical basis and practical value for the use of biochar to remediate mercury contamination in water. Biochar (RC) was prepared using corn straw as the raw material. It was then fractionated, resulting in inorganic carbon (IC), organic carbon (OC), hydroxyl-blocked carbon (BHC), and carboxyl-blocked carbon (BCC). Before and after Hg2+ adsorption, the biochar fractions were characterized by several techniques, such as energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Obtained results indicate that the reaction mechanisms of RC for Hg2+ removal mainly include electrostatic adsorption, ion exchange, reduction, precipitation, and complexation. The equilibrium adsorption capacity of RC for Hg2+ is 75.56 mg/g, and the adsorption contribution rates of IC and OC are approximately 22.4% and 77.6%, respectively. Despite the lower rate, IC shows the largest adsorption capacity, of 92.63 mg/g. This is attributed to all the mechanisms involved in Hg2+ adsorption by IC, with ion exchange being the main reaction mechanism (accounting for 39.8%). The main adsorption mechanism of OC is the complexation of carboxyl and hydroxyl groups with Hg2+, accounting for 71.6% of the total OC contribution. BHC and BCC adsorb mercury mainly via the reduction–adsorption mechanism, accounting for 54.6% and 54.5%, respectively. Among all the adsorption mechanisms, the complexation reaction of carboxyl and hydroxyl groups with Hg2+ is the dominant effect.

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 Modification of Lampung and Bayah Natural Zeolite to Enhance the Efficiency of Removal of Ammonia from Wastewater

2019 ◽  
Vol 31 (4) ◽  
pp. 873-878
Author(s):  
Tiur Elysabeth ◽  
Zulnovri ◽  
Gina Ramayanti ◽  
Setiadi ◽  
Slamet
Keyword(s):  
Ion Exchange ◽  
Adsorption Capacity ◽  
Natural Zeolite ◽  
Acid Treatment ◽  
Performance Test ◽  
Hydroxyl Groups ◽  
Ammonia Adsorption ◽  
Modified Zeolite ◽  
X Ray ◽  
Modification Process

In this research, modification of Lampung and Bayah natural zeolites was carried out to increase the zeolite’s capacity as an ammonia adsorbent. Natural zeolite is modified by acid treatment using 6 M HCl and ion exchange using 1 M NH4NO3. The modification process continued with calcination at 500 °C for 4 h. X-ray fluorescence characterization shows changes in composition in the modified zeolites. The significant increase in the Si/Al ratio occurred in the modified zeolite with acid treatment that is 10.03 for Lampung natural zeolite HCl (LNZH) and 9.20 for Bayah natural zeolite HCl (BNZH). Surface area increases due to increasing Si/Al ratio. FTIR results indicate changes in the intensity of hydroxyl groups and pyrH+ as a result of the increase in total acidity of zeolites. The zeolites performance test proves that the Bayah natural zeolite has a higher ammonia adsorption capacity than Lampung natural zeolite. Ion exchange-modified zeolite has a higher ammonia adsorption capacity than zeolite modified with acid treatment.

Physical and Thermal Properties of Chitosan

2014 ◽  
Vol 979 ◽  
pp. 315-318 ◽  
Author(s):  
W. Siriprom ◽  
K. Chantarasunthon ◽  
K. Teanchai
Keyword(s):  
Physical Properties ◽  
Thermo Gravimetric Analysis ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Biodegradable Films ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Good Agreement

This work aims at characterizing the thermal and physical properties of chitosan. The samples were evaluated for potentiality to use as raw material for biodegradable films raw material. Their thermal and physical properties have been also discussed in detail which Fourier Transform Infrared Spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA), Energy Dispersive X-Ray Fluorescence (EDXRF) and X-Ray Diffraction (XRD), respectively. The result of the XRD pattern indicated the sample has amorphous-crystalline structure and FTIR results confirmed the formation of intermolecular hydrogen bonding between the amino and hydroxyl groups of the sample. In good agreement between the EDXRF and TGA results, noticed that the removal of moisture and volatile material.

scholarly journals Selective removal of silicic acid by a gallic-acid modified resin

2019 ◽  
Vol 9 (4) ◽  
pp. 431-441
Author(s):  
Shuqin Bai ◽  
Jue Han ◽  
Cong Du ◽  
Wei Ding
Keyword(s):  
Adsorption Capacity ◽  
Gallic Acid ◽  
Silicic Acid ◽  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Selective Adsorption ◽  
Hydroxyl Groups ◽  
Acid Type ◽  
The Common ◽  
Common Anion

Abstract To remove silicic acid from aqueous solutions, a novel gallic acid-type resin (GA-type resin) was prepared by a grafting method. The effects of the adsorption capacity, pH and presence of NaCl, NaNO3, Na2SO4, and NaCO3 salts on the silicic acid removal were studied. The GA-type resin adsorbs monosilicic acid, silicate ions, and polymeric silicic acid. The adsorption capacity of 4.64–4.94 mg/g was achieved in a short adsorption time (Qm of 8.99 mg/g) and is 30–40 times larger than that of the OH-type resin. The silicic acid removal efficiency was almost unaffected by the pH and common anions when the common anion and silicic acid contents were similar, proving the GA-type resin exhibits an excellent performance for selective adsorption of silicic acid. The Temkin isotherm model can well describe the adsorption process, which is chemical adsorption, and indicates that the adsorption heat decreases with the increasing adsorption amount. The adsorption mechanism of silicic acid on the GA-type resin involves dehydration condensation reactions of the hydroxyl groups in silicic acid and gallic acid. The GA-type resin can be efficiently regenerated and reused after treatment with an HCl solution.

scholarly journals Mg-Al Mixed Oxide Adsorbent Synthesized Using FCT Template for Fluoride Removal from Drinking Water

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jifa Liu ◽  
Ping Zhao ◽  
Yue Xu ◽  
Xibin Jia
Keyword(s):  
Drinking Water ◽  
Adsorption Capacity ◽  
Mixed Oxide ◽  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
Molar Ratio ◽  
Fluoride Removal ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Fluoride Adsorption

To make full use of natural waste, a novel Mg-Al mixed oxide adsorbent was synthesized by the dip-calcination method using the fluff of the chinar tree (FCT) and an Mg(II) and Al(III) chloride solution as raw materials. The adsorbents were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The effects of the Mg/Al molar ratio and calcination temperature on the performance of the novel Mg-Al mixed oxide adsorbent were investigated. The optimized Mg-Al mixed oxide adsorbent had a Langmuir adsorption capacity of 53 mg/g. This adsorption capacity was higher than that of the separate Mg oxide and Al oxide. The synergy between Mg and Al is beneficial to the adsorption performance of the material. The fluoride adsorption capacity of the optimized Mg-Al mixed oxide adsorbent is only slightly affected by ions such as Cl−, NO3−, SO42−, Na+, and K+and is excellent for use in recycling and real water. The hydroxyl groups on the surface of the Mg-Al mixed oxide adsorbent play a key role in the adsorption of fluorine. The as-obtained novel Mg-Al mixed oxide adsorbent is an efficient and environmentally friendly agent for fluoride removal from drinking water.

Synthesis and Characterization of Carbon/Bentonite Composite

2012 ◽  
Vol 549 ◽  
pp. 703-706
Author(s):  
De Yi Zhang ◽  
Jing Wu ◽  
Bai Yi Chen ◽  
He Ming Luo ◽  
Kun Jie Wang ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Activated Carbon ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Heavy Metal Ions ◽  
Low Cost ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
Carbon Particles ◽  
Prepared Composite

In this paper, a novel carbon/bentonite composite was prepared using sucrose as carbon source and bentonite as raw material. The characterization results shown that plenty of carbon particles distribute on the surface of the composite, and an abundant of functional groups, such as SO3H, carboxylic and hydroxyl groups, were successfully introduced onto the surface of the prepared composite. The adsorption capacity of the prepared composite for typical heavy metal ions and methylene blue deys also was investigated and compared with activated carbon and bentonite, the results show that the composite shows excellent adsorprion performance for heavy metal ions, and the adsorption capacity for Cu2+and Ni2+ increase by 136% and 591% than natural bentonite, respectSuperscript textively. The prepared composite with excellent adsorption performance could be used as a low-cost alternative to activated carbon for the treatment of heavy metal ions polluted wastewater.

scholarly journals Fe-modified activated carbon obtained from biomass as a catalyst for α-pinene autoxidation

2021 ◽  
Vol 23 (2) ◽  
pp. 73-80
Author(s):  
Adrianna Kamińska ◽  
Nikola Maciejewska ◽  
Piotr Miądlicki ◽  
Karolina Kiełbasa ◽  
Joanna Sreńscek-Nazzal ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Orange Peel ◽  
Raw Material ◽  
Main Reaction ◽  
Reaction Products ◽  
Modified Activated Carbon ◽  
X Ray ◽  
Alpha Pinene ◽  
Instrumental Methods ◽  
First Time

Abstract The presented work describes the autoxidation of alpha-pinene for the first time using a catalyst based on activated carbon from biomass with introduced Fe. The raw material for the preparation of the carbon material was waste orange peel, which was activated with a KOH solution. The following instrumental methods characterized the obtained catalyst (Fe/O_AC):N2 adsorption at 77 K, XRD, UV, SEM, TEM, X-ray microanalysis, and catalytic studies. It was shown that the Fe/O_AC catalyst was very active in the autoxidation of alpha-pinene. The main reaction products were: alpha-pinene oxide, verbenone, verbenol, and campholenic aldehyde.

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.

Adsorption properties and mechanism of uranium by three biomass materials

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhe Wang ◽  
Feng-Yu Huang ◽  
Yan Liu ◽  
Fa-Cheng Yi ◽  
Yuan Feng ◽  
...  
Keyword(s):  
Particle Size ◽  
Ion Exchange ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Adsorption Mechanism ◽  
Wood Fibers ◽  
Isothermal Adsorption ◽  
Uranium Adsorption ◽  
Bamboo Fibers ◽  
Large Dosage

Abstract Wood fibers, bamboo fibers and rice husk were applied to the adsorption of uranium from aqueous solution to understand the uranium adsorption behavior and mechanism by these natural sorbents. The effects of time, adsorbent particle size, pH, adsorbent dosage, temperature and initial concentration were studied using batch technique. The adsorption mechanism was discussed by isothermal adsorption models, adsorption kinetic models. The results suggested that the three biomass adsorbents showed great efficiency of adsorption for uranium. The adsorption capacity of biosorbents of comparatively small particle size and large dosage is quite high. Uranium adsorption achieved a maximum adsorption amount at around pH 3 for wood fibers and bamboo fibers, and around pH 5 for rice husk. All isotherms fitted well to the Langmuir Freundlich and D-R equation, indicating that the adsorption process is favorable and dominated by ion exchange. Rice husk had a highest adsorption capacity, followed by bamboo fibers, while wood fibers had little uranium adsorption under the studied conditions, and the adsorption capacity was 12.22, 11.27 and 11.04 mg/g, respectively. The equilibrium data was well represented by the pseudo-second-order kinetics, indicating that the adsorption rate was controlled by chemical adsorption. Ion exchange was the main adsorption mechanism, and the exchange ions were mainly Na+ and K+.

Adsorption Mechanism of Rectorite Modified by Lithium

2014 ◽  
Vol 919-921 ◽  
pp. 2017-2021
Author(s):  
Yin An Ming ◽  
Ying Ru Wang ◽  
Zheng Liu ◽  
Fu Rong Zhou
Keyword(s):  
Methylene Blue ◽  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Interlayer Spacing ◽  
Blue Dye ◽  
Adsorption Efficiency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Index Measurement ◽  
Infrared Spectrophotometer

In this paper, the mechanism that lithium-modified rectorite (Rec-Li) and raw rectorite adsorbed methylene blue dye in wastewater was investigated, and the adsorption properties of the two adsorbents were also compared. The results showed that the static saturated adsorption capacity of raw rectorite was 77.75mg/g, however, the capacity of lithium-modified rectorite was up to 189.62mg/g, the adsorption efficiency was increased by 144%. Therefore, the adsorption capacity of Rec-Li to methylene blue was much higher than raw rectorite. The Rec-Li and raw rectorite were characterized respectively by means of fourier transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and colloid index measurement. The analysis indicated that, after modification by lithium, the colloid index was changed from 12mL/3g to 198mL/3g and the interlayer spacing was changed from 0.01~0.1μm to 1~1.5μm. With the increasing of the colloid index, the dispersion effect of adsorbent in wastewater and the contact area between adsorbent and pollutants were improved. And the increase of interlayer spacing was conducive to pollutants entering the hole and so that the adsorption capacity of Rec-Li was increased significantly.

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