Carboxyl and hydroxyl groups enhance ammonium adsorption capacity of iron (III) chloride and hydrochloric acid modified biochars

In this study, the adsorption capacity of expanded perlite (EP) for benzene at low concentrations in water was investigated after EP was treated with sodium hydroxide (NaOH). IR spectra used to characterize the modified EP showed that there was no bonding between NaOH and the hydroxyl groups on the surface of EP. However, the NaOH provided a basic medium for negatively charged surface oxide ions (-SO-) to form on EP. This fact was corroborated by pH readings of the modification solution. This reduced in pH from 10 to 9 at the end of the reaction which indicated that the hydroxyl OH- groups on the EP underwent deprotonation and hence releases H+ into the solution, and also positive sites on EP adsorbed OH- ions from the base solution. Mahir et al. in their paper Zeta potential of unexpanded and expanded perlite samples in various electrolyte media confirmed that EP has no isoelectric point and exhibits negative zeta potential in the pH range of 2-11. The surface oxides (-SO-) were believed to have given EP it adsorptive potential. Adsorption isotherm values correlated reasonably well with the Langmuir isotherm model and it parameters (qo and K) were obtained using linear regression analysis. A maximum adsorption capacity (qo) value of 19.42 mg/g was achieved.

Download Full-text

Adsorption Behavior of Inorganic and Organic Phosphate by Iron Manganese Plaques on Reed Roots in Wetlands

Sustainability ◽

10.3390/su10124578 ◽

2018 ◽

Vol 10 (12) ◽

pp. 4578 ◽

Cited By ~ 3

Author(s):

Yingjie Zhu ◽

Xiaoli Du ◽

Can Gao ◽

Zhenya Yu

Keyword(s):

Adsorption Capacity ◽

Fine Particles ◽

Freundlich Isotherm ◽

Organic Phosphate ◽

Photoelectron Spectra ◽

Phosphate Adsorption ◽

Isotherm Models ◽

Hydroxyl Groups ◽

Iron Manganese ◽

Inorganic And Organic

Inorganic and organic phosphate adsorption by iron–manganese (Fe–Mn) plaques extracted from reed roots was investigated. Scanning electron microscopy indicated the roots had rough surfaces and fine particles attached. X-ray photoelectron spectra indicated that Fe and Mn in the Fe–Mn plaques were mainly in the +III and +IV oxidation states, respectively. The contact time, initial phosphate concentration, and temperature effects on inorganic and organic phosphate adsorption were investigated by performing batch tests. Pseudo-second-order model described inorganic and organic phosphate adsorption, indicating the chemisorption was the dominant adsorption process. Langmuir and Freundlich isotherm models were fitted to the equilibrium data, and the Langmuir model fitted best. The maximum inorganic and organic phosphate adsorption capacities at 298 K were 7.69 and 3.66 mg/g, respectively. The inorganic and organic phosphate adsorption processes were spontaneous and exothermic. The inorganic phosphate adsorption capacity was higher than the organic phosphate adsorption capacity, and the presence of organic phosphate did not negatively affect adsorption at inorganic to organic phosphate molar ratios between 1:1 and 3:1. Fourier-transform infrared spectra before and after adsorption showed abundant functional groups on Fe–Mn plaques and that phosphate was probably adsorbed via replacement of hydroxyl groups and inner-sphere surface complexation.

Download Full-text

Adsorption Capacity of Ca2+ by Hydrochloric Acid Activated Kaolin

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/926/1/012082 ◽

2021 ◽

Vol 926 (1) ◽

pp. 012082

Author(s):

N Wahyuni

Keyword(s):

Hydrochloric Acid ◽

Adsorption Capacity ◽

Calcium Ions ◽

Contact Time ◽

Maximum Adsorption Capacity ◽

High Concentration ◽

Straightforward Method ◽

Diamine Tetraacetate ◽

Ca Ions ◽

Time Variations

Abstract A high concentration of calcium ions in water is a problem as it can cause blockages in engine pipes. Adsorption is a relatively cheap and straightforward method that can be used to reduce the calcium ion content in water. Kaolin is a mineral that has a potential as an adsorbent and whose adsorption capacity can be increased by activation. This research studied the adsorption capacity of activated kaolin by hydrochloric acid against Ca2+ ions. Kaolin was chemically activated using 6 M HCl solution for 24 hours. The adsorption contact time in batches was varied with time variations of 30, 90, 150, and 180 minutes. The maximum adsorption capacity of activated kaolin to the Ca2+ was determined by varying the initial concentrations of water samples, namely 4, 7, 10, and 13 mg/L. The concentration of Ca2+ was determined by a titration method using ethylene diamine tetraacetate (EDTA). The results showed that the activation of kaolin with 6 M HCl at the optimum contact time of adsorption, namely 150 minutes, increased the percentage of adsorbed Ca ions to 2 times of that of natural kaolin, from 33.3% to 68.3%. Based on the Langmuir equation, the maximum adsorption capacity of calcium ions by activated kaolin HCl 6 M increased 1.7 times from natural kaolin to 0.346 mg/g.

Download Full-text

Mn-Fe Layered Double Hydroxide Intercalated with Ethylene-Diaminetetraacetate Anion: Synthesis and Removal of As(III) from Aqueous Solution around pH 2–11

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17249341 ◽

2020 ◽

Vol 17 (24) ◽

pp. 9341

Author(s):

Guifeng Liu ◽

Zongqiang Zhu ◽

Ningning Zhao ◽

Yali Fang ◽

Yingying Gao ◽

...

Keyword(s):

Adsorption Capacity ◽

Layered Double Hydroxides ◽

Interlayer Spacing ◽

Maximum Adsorption Capacity ◽

Hydroxyl Groups ◽

Surface Hydroxyl ◽

Xps Characterization ◽

Ph Range ◽

Double Hydroxide ◽

Double Hydroxides

A novel adsorbent Mn-Fe layered double hydroxides intercalated with ethylenediaminete-traacetic (EDTA@MF-LDHs) was synthesized by a low saturation coprecipitation method. The behavior and mechanism of As(III) removed by EDTA@MF-LDHs were investigated in detail in comparison with the carbonate intercalated Mn-Fe layered double hydroxides (CO3@MF-LDHs). The results showed that EDTA@MF-LDHs had a higher removal efficiency for As(III) than As(V) with a broader pH range than CO3@MF-LDH. The large adsorption capacity of EDTA@MF-LDHs is related to its large interlayer spacing and the high affinity of its surface hydroxyl groups. The maximum adsorption capacity for As(III) is 66.76 mg/g at pH 7. The FT-IR and XPS characterization indicated that the removal mechanism of the As(III) on EDTA@MF-LDHs include surface complexation, redox, and ion exchange.

Download Full-text

Studies on Copper Ion Adsorption Using Pectin/Functionalized-Silica Coated Cellulose

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1131.210 ◽

2015 ◽

Vol 1131 ◽

pp. 210-214

Author(s):

Radchada Buntem ◽

Thitiwat Tanyalax

Keyword(s):

Hydrochloric Acid ◽

Adsorption Capacity ◽

Filter Paper ◽

Copper Ion ◽

Silica Sol ◽

Ion Adsorption ◽

Functionalized Silica ◽

Solution Ph ◽

Optimum Ph ◽

Sem Micrograph

The pectin/functionalized silica coated filter paper (FILPSL2) was used for copper ion adsorption. Silica sol (1), prepared by mixing ethanol, water, TEOS and hydrochloric acid, was slowly added into pectin solution. A piece of filter paper (2 cm x 2 cm) was immersed in the silica-pectin solution for 1 hr. The coated filter paper was dried at room temperature and then oven-dried at 50 °C for 6 hrs to obtain FILPS. The silica sol (2) was subsequently prepared by mixing ethanol, water, N-[3-(Trimethoxysilyl) propyl] ethylenediamine (L2) and hydrochloric acid. The FILPS was immersed in silica sol (2) and the coated paper was oven-dried at 50 °C for 6 hrs to obtain FILPSL2. The SEM micrograph of uncoated Filter paper (FIL) and FILPSL2 showsa characteristic woven pattern. For copper ion adsorption, FILPSL2 was put into 0.1 M of CuCl2solution (pH 2, 25 °C). The color of the paper changes from off-white to intense blue within 5 min due to the complex between amino group of functionalized silica and Cu2+ as evidenced from IR spectroscopy.The equilibrium adsorption percentage and adsorption capacity were 27.10 and 5.5 x 10-3 respectively. The concentrations of copper ion solutions were varied to 10-2and 10-3M at this pH. The lower concentration of copper ion results in the higher adsorption percentage. While the lower concentration of copper ion results in the lower adsorption capacity. The adsorption was also experimented at pH 3.The similar trend was obtained. The optimum pH for adsorption for all concentrations was 2. The effect of interferences on the copper ion adsorption depends on the pH. At pH 2, Ni2+ has a stronger effect. While Cd2+ has a stronger effect at pH 3. The desorption was performed using 0.2 M CH3COOH solution. The complete desorption occurred within 30 min.

Download Full-text

Research on Purification of Attapulgite Clay and Adsorption Characteristics for Metal Cations

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.1719 ◽

2009 ◽

Vol 79-82 ◽

pp. 1719-1722

Author(s):

Zhi Hong Zhang ◽

Shao Yu Zhang ◽

Xue Dong Liu

Keyword(s):

Electron Microscope ◽

Hydrochloric Acid ◽

Adsorption Capacity ◽

Transmission Electron Microscope ◽

Metal Cations ◽

Fiber Structure ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Attapulgite Clay

Attapulgite clay(ATP) from Xuyi county of China was purified by a wet method then treated with NaOH and 1.0 mol/L, 2.0 mol/L and 3.0 mol/L solutions of HCl. Transmission electron microscope(TEM) and X-ray diffraction (XRD) were used to characterize treated ATP. Results showed that wet purification could remove most of impurities. Treatment by alkaline and HCl of 1.0 mol/L and 2.0 mol/L could increase purity while treatment of 3.0 mol/L hydrochloric acid could dissolve some element of ATP so much as form SiO2 and destroy fiber structure to clips. Adsorption experiments of Fe3+ and Ni2+ from aqueous solutions were done using original ATP, purified ATP and treated ATP as absorbents. Results showed that Attapulgite could adsorb metal cations in significant amounts. Sodium hydroxide activation had little influence on adsorption capacity. Influences of acid treatments to ATP on adsorption capacity varied on different concentration solutions.

Download Full-text

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

Journal of Water Reuse and Desalination ◽

10.2166/wrd.2019.030 ◽

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.

Download Full-text

Adsorptive removal of phosphate by a Fe–Mn–La tri-metal composite sorbent: Adsorption capacity, influence factors, and mechanism

Adsorption Science & Technology ◽

10.1177/0263617420942709 ◽

2020 ◽

Vol 38 (7-8) ◽

pp. 254-270

Author(s):

Yuanrong Zhu ◽

Xianming Yue ◽

Fazhi Xie

Keyword(s):

Aqueous Solutions ◽

Adsorption Capacity ◽

Photoelectron Spectroscopy ◽

Phosphate Removal ◽

Maximum Adsorption Capacity ◽

Hydroxyl Groups ◽

Metal Composite ◽

Order Kinetic ◽

Composite Sorbent ◽

Composite Adsorbent

Reducing input of phosphorus is the key step for control of eutrophication and algal blooming in freshwater lakes. Adsorption technology is a cost-effective technology for phosphate removal in water for the purpose. Thus, in this study, a novel Fe–Mn–La tri-metal composite sorbent was developed, and then evaluated for phosphate removal. The results showed that the maximum adsorption capacity could be approached to 61.80 mg g−1 at 25°C under pH of 6.03. Adsorption of phosphate by Fe–Mn–La tri-metal composite adsorbent fitted better by pseudo-second-order kinetic equation and Langmuir model, which suggested that the adsorption process was surface chemical reactions and mainly in a monolayer coverage manner. The thermodynamic study indicated that the adsorption reaction was an endothermic process. The phosphate removal gradually decreased with the increasing of pH from 3.02 to 11.00. The sequence of coexisting anions competing with phosphates was that CO32− > Cl− > SO42− > NO3−. Dissolved organic matter, fulvic acid as a representative, would also decrease adsorption capacities of phosphate by Fe–Mn–La tri-metal composite adsorbents. Adsorption capacity would be decreased with increasing addition of adsorbents, while removal efficiency would be increased in this process. The Fe–Mn–La tri-metal composite adsorbent showed a good reusability when applied to removal of dissolved phosphate from aqueous solutions. The Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy analyses indicated that some hydroxyl groups (–OH) on the surface of adsorbent were replaced by the adsorbed PO43−, HPO42−, or H2PO4−. Aggregative results showed that the novel Fe–Mn–La tri-mental composite sorbent is a very promising adsorbent for the removal of phosphate from aqueous solutions.

Download Full-text

Studies on the lignin of Eucalyptus regnans F. Muell. VII. The acid hydrolysis of ethanyol lignin-A

Australian Journal of Chemistry ◽

10.1071/ch9530156 ◽

1953 ◽

Vol 6 (2) ◽

pp. 156 ◽

Cited By ~ 2

Author(s):

JWT Merewether

Keyword(s):

Hydrochloric Acid ◽

Acid Hydrolysis ◽

Carbonyl Group ◽

Dilute Hydrochloric Acid ◽

Hydroxyl Groups ◽

Eucalyptus Regnans ◽

Ethoxyl Group ◽

Hydrolysis Of

Ethanol lignin-A from the ethanolysis of Eucalyptus regnans P. Muell. has been hydrolysed with dilute hydrochloric acid with the object of ascertaining whether the combined ethoxyl is present as an acetal or as ether. Hydrolysis with 12 per cent. hydrochloric acid was found to split off one ethoxyl group, while hydrolysis with 20 per cent. acid brought about complete de-ethylation. The de-ethylated ethanol lignin-A contained one carbonyl group less and two hydroxyl groups more than the original ethanol lignin-A. These results lend no support to the hypothesis that alcohol lignins are acetals, and favour the theory that the combined alkoxyl is probably present as ether.

Download Full-text

Sonicated Zeolitic Imidazolate Frameork-8 derived Nitrogen-doped hierarchical nanoporous carbon for efficient capture and reversible storage of radioiodine

10.21203/rs.3.rs-157131/v1 ◽

2021 ◽

Author(s):

Elvis Miensah ◽

Jiuyu Chen ◽

Aotian Gu ◽

Peng Wang ◽

Ying Liu ◽

...

Keyword(s):

Adsorption Capacity ◽

Surface Area ◽

Nanoporous Carbon ◽

Industrial Applications ◽

Large Surface Area ◽

Hydroxyl Groups ◽

High Adsorption ◽

Fast Kinetics ◽

Nitrogen Doped ◽

High Adsorption Capacity

Abstract Iodine plays a significant role in industry and in chemical processes within living organisms. However, radioiodine exposure possess threats such as thyroid cancer to humans, when they are released into the environment when using nuclear technology and through nuclear accidents. Its capture and storage is critical to safeguard industrial applications while preventing environmental leakages. Herein we report efficient radioiodine capture using a hierarchical nitrogen-doped, large surface area, nanoporous carbon derived from ultrasonication of ZIF-8. The carbon exhibited high adsorption capacity of 434 wt% gravimetrically and 1418 mgg− 1 in cyclohexane solution with fast kinetics and high recoverability. We deduced the high adsorption capacity to be due to the large surface area with micro and mesopores, presence of hydroxyl groups acting as electron donors and the presence of nitrogen, which interacts strongly with the electron-deficient iodine (I2). Moreover, the process best fits the pseudo-second-order and Freundlich models with multilinearity observed with Webber-Morris model. Because of its comparatively lower cost, large surface area, facile preparation, good regeneration and fast kinetics, the as-prepared porous carbon shows exceptional promise as radioiodine adsorbent.

Download Full-text