scholarly journals A Functionalized Silicate Adsorbent and Exploration of Its Adsorption Mechanism

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1820 ◽  
Author(s):  
Hanzhi Lin ◽  
Tao Chen ◽  
Bo Yan ◽  
Zulv Huang ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Quartz Sand ◽  
Adsorption Mechanism ◽  
Raw Material ◽  
Utilization Efficiency ◽  
Isotherm Models ◽  
Separation Coefficient ◽  
Maximum Adsorption Capacity ◽  
Oh Groups ◽  
Activating Agent

Active silicate materials have good adsorption and passivation effects on heavy metal pollutants. The experimental conditions for the preparation of active silicate heavy metal adsorbent (ASHMA) and the adsorption of Cu(II) by ASHMA were investigated. The optimum preparation conditions of ASHMA were as follows: 200 mesh quartz sand as the raw material, NaOH as an activating agent, NaOH/quartz sand = 0.45 (mass fraction), and calcination at 600 °C for 60 min. Under these conditions, the active silicon content of the adsorbent was 22.38% and the utilization efficiency of NaOH reached 89.11%. The adsorption mechanism of Cu(II) on the ASHMA was analyzed by the Langmuir and Freundlich isotherm models, which provided fits of 0.99 and 0.98, respectively. The separation coefficient (RL) and adsorption constant (n) showed that the adsorbent favored the adsorption of Cu(II), and the maximum adsorption capacity (Qmax) estimated by the Langmuir isotherm was higher than that of 300 mg/L. Furthermore, adsorption by ASHMA was a relatively rapid process, and adsorption equilibrium could be achieved in 1 min. The adsorbents were characterized by FT-IR and Raman spectroscopy. The results showed that the activating agent destroyed the crystal structure of the quartz sand under calcination, and formed Si-O-Na and Si-OH groups to realize activation. The experimental results revealed that the adsorption process involved the removal of Cu(II) by the formation of Si-O-Cu bonds on the surface of the adsorbent. The above results indicated that the adsorbent prepared from quartz sand had a good removal effect on Cu(II).

scholarly journals Utilization to Remove Pb (II) Ions from Aqueous Environments Using Waste Fish Bones by Ion Exchange

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Bayram Kizilkaya ◽  
A. Adem Tekınay
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Mechanism ◽  
Cost Effective ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Fish Bones ◽  
Adsorption Capacities ◽  
Aqueous Environments ◽  
Equilibrium Data ◽  
Pseudo Second Order

Removal of lead (II) from aqueous solutions was studied by using pretreated fish bones as natural, cost-effective, waste sorbents. The effect of pH, contact time, temperature, and metal concentration on the adsorption capacities of the adsorbent was investigated. The maximum adsorption capacity for Pb (II) was found to be 323 mg/g at optimum conditions. The experiments showed that when pH increased, an increase in the adsorbed amount of metal of the fish bones was observed. The kinetic results of adsorption obeyed a pseudo second-order model. Freundlich and Langmuir isotherm models were applied to experimental equilibrium data of Pb (II) adsorption and the value ofRLfor Pb (II) was found to be 0.906. The thermodynamic parameters related to the adsorption process such asEa,ΔG°,ΔH°, andΔS° were calculated andEa,ΔH°, andΔS° were found to be 7.06, 46.01 kJ mol−1, and 0.141 kJ mol−1K−1for Pb (III), respectively.ΔH° values (46.01 kJmol−1) showed that the adsorption mechanism was endothermic. Weber-Morris and Urano-Tachikawa diffusion models were also applied to the experimental equilibrium data. The fish bones were effectively used as sorbent for the removal of Pb (II) ions from aqueous solutions.

From Wastes To Functions: Preparation of Layered Double Hydroxides From Industrial Waste And Its Removal Performance Towards Phosphates

2021 ◽  
Author(s):  
Liping Xiao ◽  
Yan Li ◽  
Qiaoping Kong ◽  
Yunlong Lan
Keyword(s):  
Langmuir Isotherm ◽  
Industrial Waste ◽  
Physical Adsorption ◽  
Raw Material ◽  
Isotherm Models ◽  
Particle Diffusion ◽  
Maximum Adsorption Capacity ◽  
Membrane Diffusion ◽  
Phosphorus Adsorption ◽  
Intra Particle Diffusion

Abstract To control eutrophication and recover phosphate from wastewater, a calcium carbide slag and red mud composite material (CR-LDH) was prepared using industrial waste as raw material for phosphorus adsorption. The morphology and structure of synthesized CR-LDH was characterized by FT-IR, SEM, EDS and XRD measurements. The experimental data can be well described by pseudo-second-order kinetics and Langmuir isotherm models, suggesting that the adsorption process of CR-LDH with respect to phosphate is a chemical and monolayer process. The theoretical maximum adsorption capacity obtained by Langmuir isotherm model is 16.06 mg·g-1 at 25 oC. The intra-particle diffusion model fitting results indicated that the adsorption of phosphate by CR-LDH was controlled by both liquid membrane diffusion and intra-particle diffusion. Phosphate was bound to CR-LDH via synergistic effect of physical adsorption, ion exchange, anion intercalation and chemical precipitation as evidenced from a combination of microscopic analysis and adsorption mechanism study. The actual phosphate-containing wastewater investigation showed that CR-LDH not only exhibited good removal effect on phosphate, but also could greatly reduce turbidity, COD and ammonia nitrogen, which was suitable for disposal of practical wastewater. These results indicate that CR-LDH can be considered as potential adsorbent for the treatment of phosphate-containing wastewater, which will be helpful to achieve the goal of "treating waste with waste and turning waste into treasure".

scholarly journals Enhanced heavy metal removal from an aqueous environment using an eco-friendly and sustainable adsorbent

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wanqi Zhang ◽  
Yuhong An ◽  
Shujing Li ◽  
Zhechen Liu ◽  
Zhangjing Chen ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Mechanism ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Raw Material ◽  
Maximum Adsorption Capacity ◽  
Aqueous Environment ◽  
Adsorption Parameters ◽  
Solution Ph ◽  
Sodium Bentonite

Abstract Thiol-lignocellulose sodium bentonite (TLSB) nanocomposites can effectively remove heavy metals from aqueous solutions. TLSB was formed by using –SH group-modified lignocellulose as a raw material, which was intercalated into the interlayers of hierarchical sodium bentonite. Characterization of TLSB was then performed with BET, FTIR, XRD, TGA, PZC, SEM, and TEM analyses. The results indicated that thiol-lignocellulose molecules may have different influences on the physicochemical properties of sodium bentonite, and an intercalated–exfoliated structure was successfully formed. The TLSB nanocomposite was subsequently investigated to validate its adsorption and desorption capacities for the zinc subgroup ions Zn(II), Cd(II) and Hg(II). The optimum adsorption parameters were determined based on the TLSB nanocomposite dosage, concentration of zinc subgroup ions, solution pH, adsorption temperature and adsorption time. The results revealed that the maximum adsorption capacity onto TLSB was 357.29 mg/g for Zn(II), 458.32 mg/g for Cd(II) and 208.12 mg/g for Hg(II). The adsorption kinetics were explained by the pseudo-second-order model, and the adsorption isotherm conformed to the Langmuir model, implying that the dominant chemical adsorption mechanism on TLSB is monolayer coverage. Thermodynamic studies suggested that the adsorption is spontaneous and endothermic. Desorption and regeneration experiments revealed that TLSB could be desorbed with HCl to recover Zn(II) and Cd(II) and with HNO3 to recover Hg(II) after several consecutive adsorption/desorption cycles. The adsorption mechanism was investigated through FTIR, EDX and SEM, which demonstrated that the introduction of thiol groups improved the adsorption capacity. All of these results suggested that TLSB is an eco-friendly and sustainable adsorbent for the extraction of Zn(II), Cd(II) and Hg(II) ions in aqueous media.

Preparation and characterization of Ca(II) cross-linking modified pectin microspheres for Pb(II) adsorption

2019 ◽  
Vol 79 (8) ◽  
pp. 1484-1493
Author(s):  
Fen Li ◽  
Zhao Xu ◽  
Xiaoyan Wen ◽  
Xiaoyong Li ◽  
Yanhong Bai ◽  
...  
Keyword(s):  
Adsorption Mechanism ◽  
Isotherm Models ◽  
Cross Linking ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Wastewater Purification ◽  
Adsorption Ability ◽  
Pectic Acid ◽  
Pseudo Second Order

Abstract A novel adsorbent, composed of cross-linked de-esterified pectin microspheres, was prepared via cross-linking with Ca(II) and modification by de-esterified pectin, low-methoxyl pectin (LMP) and pectic acid (PA). Fourier transform infrared (FTIR), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) were applied too, exhibiting a successful fabrication, good adsorption ability, and well-defined surface microstructure beneficial to Pb(II) adsorption. The adsorption ability of pectin microspheres (PMs), low-methoxyl pectin microspheres (LMPMs) and pectic acid microspheres (PAMs) for Pb(II) in aqueous solution were explored. The maximum adsorption capacity of PMs, LMPMs and PAMs was 127 mg·g−1, 292 mg·g−1 and 325 mg·g−1 at pH 5.0 respectively, indicating a great improvement of LMPMs and PAMs in the adsorption ability for Pb(II) compared with PMs. Furthermore, the adsorption mechanism was proposed. The experimental data were well fitted with pseudo-second-order kinetic and Langmuir isotherm models. Five-cycle reusability tests demonstrated that microspheres could be used repeatedly. All the results confirmed that LMPMs and PAMs, which presented outstanding adsorption capability and reusability, could be a good candidate for wastewater purification.

The Effective Removal of Congo Red Dye from Aqueous Solution Using Fly Ash/CeO2 Composite Material

2014 ◽  
Vol 535 ◽  
pp. 671-674 ◽  
Author(s):  
Lei Ding ◽  
Bei Gang Li ◽  
Jing Mi
Keyword(s):  
Aqueous Solution ◽  
Fly Ash ◽  
Congo Red ◽  
Ph Value ◽  
Removal Rate ◽  
Langmuir Model ◽  
Raw Material ◽  
Precipitation Method ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity

Fly ash/CeO2 composite adsorbent (FA/CeO2) was prepared by HCl treatment and precipitation method using a low-cost waste fly ash (FA) as the raw material and used for the removal of Congo Red (CR) from aqueous solution. Effects of important parameters such as contact time, initial dye concentration, pH value and temperature were explored. Adsorption equilibrium and isotherms were investigated. The adsorption of CR onto FA/CeO2 is a fast process and to achieve a basic balance in 30 minutes. The removal of CR is strongly pH-dependent. FA/CeO2 is an effective adsorbent for the CR removal with removal rate of 98.8% when initial CR concentration is 1000 mg/L. The experimental isotherm data were analyzed using Langmuir and Freundlich isotherm models. The results revealed that the adsorption behavior of CR on FA/CeO2 fitted well with the Langmuir model at different temperatures. The maximum adsorption capacity obtained by Langmuir model is 232.56 mg/g which is nearly consistent with the actual adsorption value of 230.01 mg/g at 298K. The Adsorption amount decreases with increasing temperature, but the variation of the amplitude is very small.

scholarly journals Biochar from Rice Husk as Efficient Biosorbent for Procion Red Removal from Aqueous Systems

2021 ◽  
pp. 79-91
Author(s):  
Neza R. Palapa ◽  
Tarmizi Taher ◽  
Novie Juleanti ◽  
Normah Normah ◽  
Aldes Lesbani
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
Rice Husk ◽  
Electromagnetic Waves ◽  
Raw Material ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Aqueous Systems ◽  
Aquatic Life ◽  
Mutagenic Effects

Numerous reports have elucidated the use of biochar (BC) to adsorb dyes from wastewater. However, its applicability for adsorbing Procion Red, which causes carcinogenic and mutagenic effects on aquatic life, has not been studied. In this work, biochar produced from rice husk in Sumatera, Indonesia was used as a biosorbent for Procion Red removal from aqueous systems. Rice husk-BC was characterised using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, surface area specific analysis, and scanning electron microscopy (SEM) for mor-phological analysis. The characterisation showed a (002) reflection peak at 2θ = 23° with broad and quite intense diffraction, which indicates reflection of electromagnetic waves by silicates, oxides and carbon present in the rice husk-BC. The surface area and SEM morphologies confirm that after pyrolysis, the surface of the rice husk changed. The FTIR spectra confirm the presence of functional groups such as the carboxylic acids and aromatic compounds. The surface area of rice husk-BC was up to ten times that of its raw material. The results of adsorption studies indicate that adsorption of Procion Red on rice husk-BC follows a pseudo-second-order (PSO) reaction with a rate constant of 0.044 min-1 and Langmuir isotherm models with a coefficient of correlation close to unity. The maximum adsorption capacity increased from 36.900 mg g-1 for the rice husk to 84.034 for the rice husk-BC. Thermodynamic analysis showed positive enthalpy and entropy, indicating that Procion Red adsorption is endothermic; thus, the Gibbs energy values decreased with increase in temperature, indicating that high temperatures are favourable for the adsorption process. Furthermore, the study of adsorption of Procion Red on rice husk-BC and regeneration of the adsorption capacity of rice husk-BC showed the largest drop in the fourth and last cycle.

Applications of Bentonite to Soil Decontamination

2018 ◽  
Vol 69 (7) ◽  
pp. 1695-1698
Author(s):  
Marin Rusanescu ◽  
Carmen Otilia Rusanescu ◽  
Gheorghe Voicu ◽  
Mihaela Begea
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Laboratory Experiments ◽  
Experimental Studies ◽  
Heavy Metal Concentration ◽  
Polluted Soil ◽  
Raw Material ◽  
Soil Decontamination ◽  
Metal Retention ◽  
Removal Of Heavy Metals

A calcium bentonite from Orasu Nou deposit (Satu Mare Romania) was used as raw material. We have conducted laboratory experiments to determine the influence of bentonite on the degree of heavy metal retention. It has been observed that the rate of retention increases as the heavy metal concentration decreases. Experimental studies have been carried out on metal retention ( Zn) in bentonite. In this paper, we realized laboratory experiments for determining the influence of metal (Zn) on the growth and development of two types of plants (Pelargonium domesticum and Kalanchoe) and the effect of bentonite on the absorption of pollutants. These flowers were planted in unpolluted soil, in heavy metal polluted soil and in heavy metal polluted soil to which bentonite was added to observe the positive effect of bentonite. It has been noticed that the flowers planted in unpolluted soil and polluted with heavy metals to which bentonite has been added, the flowers have flourished, the leaves are still green and the plants whose soils have been polluted with heavy metals began to dry after 6 days, three weeks have yellowish leaves and flowers have dried. Experiments have demonstrated the essential role of bentonite for the removal of heavy metals polluted soil.

Research status of microwave-assisted reduction technology of pyrolusite

2020 ◽  
Vol 07 ◽  
Author(s):  
Li Qiannan ◽  
Ling Yeqing ◽  
Zheng Hewen ◽  
Yang Zhi
Keyword(s):  
Metallurgical Industry ◽  
Raw Material ◽  
Utilization Efficiency ◽  
Low Grade ◽  
Manganese Ore ◽  
Effective Utilization ◽  
Research Status ◽  
Strategic Position ◽  
Research Intensity ◽  
Stable Development

: Manganese ore is an important metallurgical raw material that holds an important strategic position in the national economy of China. However, the grade of manganese ore in the country is mostly low, and the utilization efficiency of lowgrade manganese ore resources is low, which seriously restrict the healthy and stable development of China’s metallurgical industry. As a new green heating method, microwave is expected to address the problems of conventional methods and realize the effective utilization of low-grade manganese ore. In this paper, the research status of the microwave composite reduction of pyrolusite in recent years is reviewed. Microwave plays an important role in metallurgy, and it is the current direction pursued to improve the research intensity of microwave heating and extend it to actual industrial processes.

scholarly journals Ag-Functionalized Si Nanowire Arrays Aligned Vertically for SERS Detection of Captured Heavy Metal Ions by BSA

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 685
Author(s):  
Ai-Huei Chiou ◽  
Jun-Luo Wei ◽  
Ssu-Han Chen
Keyword(s):  
Heavy Metal ◽  
Raman Scattering ◽  
Metal Ions ◽  
Metal Ion ◽  
Heavy Metal Ions ◽  
Great Promise ◽  
Ag Nps ◽  
Water Contact ◽  
Oh Groups ◽  
Si Nanowire

A novel surface-enhanced Raman scattering (SERS)-based probe to capture heavy metal ion (Zn2+) by bovine serum albumin (BSA) using Si-nanowire (SiNW) arrays with silver nanoparticles (AgNPs) was developed. A layer with AgNPs was deposited on the SiNW surface by RF magnetron sputtering for enhancement of SERS signals. Using a high-resolution transmission electron microscope (HRTEM), the observation reveals that the AgNP layer with depths of 30–75 nm was successfully deposited on SiNW arrays. The Ag peaks in EDS and XRD spectra of SiNW arrays confirmed the presence of Ag particles on SiNW arrays. The WCA observations showed a high affinity of the Ag–SiNW arrays immobilized with BSA (water contact angle (WCA) = 87.1°) and ZnSO4 (WCA = 8.8°). The results of FTIR analysis illustrate that the conjugate bonds exist between zinc sulfate (ZnSO4) and –OH groups/–NH groups of BSA. The resulting SiNWs/Ag NPs composite interfaces showed large Raman scattering enhancement for the capture of heavy metal ions by BSA with a detection of 0.1 μM. BSA and ZnSO4 conjugations, illustrating specific SERS spectra with high sensitivity, which suggests great promise in developing label-free biosensors.

scholarly journals Fly Ash Coated with Magnetic Materials: Improved Adsorbent for Cu (II) Removal from Wastewater

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Maria Harja ◽  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Dumitru Daniel Herea ◽  
...  
Keyword(s):  
Fly Ash ◽  
Adsorption Capacity ◽  
Copper Ions ◽  
Synthetic Wastewater ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Copper Adsorption ◽  
X Ray

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.

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