scholarly journals Synthesis and Characterization of Different Crystalline Calcium Silicate Hydrate: Application for the Removal of Aflatoxin B1 from Aqueous Solution

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Lu Zeng ◽  
Ligang Yang ◽  
Shuping Wang ◽  
Kai Yang
Keyword(s):  
Adsorption Kinetics ◽  
Aflatoxin B1 ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Order Kinetic ◽  
Hydrothermal Conditions ◽  
Calcium Silicate Hydrates ◽  
Pseudo Second Order

Different crystalline calcium silicate hydrates (CSH) were synthesized under specific hydrothermal conditions and several methods were used to analyze samples. Amorphous calcium silicate hydrates (ACSH) mainly consists of disordered calcium silicate hydrate gel (C-S-H gel) and crystalline calcium silicate hydrates (CCSH) consists of crystallized tobermorite. The adsorption of carcinogenic aflatoxin B1 (AFB1) onto ACSH and CCSH was investigated. The adsorption kinetics was studied using pseudo-first-order and pseudo-second-order kinetic models and intraparticle diffusion model. The pseudo-second-order model provided the best correlation and the intraparticle diffusion controlled the adsorption process of AFB1 onto CCSH. Adsorption isotherm parameters were obtained from Langmuir and Freundlich and the adsorption data fitted to Freundlich much better. Based on the results of N2adsorption/desorption, adsorption kinetics, and adsorption isotherms, the adsorption mechanism of AFB1 onto CCSH was developed. All results indicate that CCSH has a great potential to be a safe, easy-made, and cost-effective material for the control of AFB1 contamination.

scholarly journals Adsorption of Pb Ions from Oily Wastewater by Anthraquinone Modified Carbon Nanotube

2021 ◽  
Vol 15 (1) ◽  
pp. 89-97
Author(s):  
Vahid Moghaddam Nansa ◽  
◽  
Maryam Otadi ◽  
Amir Heydarinasab ◽  
Rahebeh Amiri ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Adsorption Kinetics ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Order Kinetic ◽  
Batch Mode ◽  
Controllable Factors ◽  
Pseudo Second Order ◽  
Pb Ions ◽  
Four Levels

The aim of this research was to investigate the adsorption properties of anthraquinone modified carbon nanotube (ACNT) in oily wastewaters containing Pb ions. The modified adsorbents were characterized using Fourier transform infra-red spectroscopy and SEM analysis. The adsorption and regeneration studies were conducted in batch mode using a Taguchi (L16) orthogonal array to optimize experimental runs. The controllable factors used in this study consisted of: pH of the solution (A); adsorbent dosage (B); adsorbent type (C); contact time (D); temperature (F). The effects of each factor were studied at four levels on the removal efficiency of metals from aqueous solution. Concentrations of metal ions were assessed by atomic absorption spectrometer. The total optimum adsorptive removal of lead ions was obtained with C0 = 10 mg•l-1, T = 338 K, pH = 6, m = 0.020 mg and t = 60 min. The Langmuir model was representative to simulate adsorption isotherms. The adsorption kinetics of Pb adsorption by ACNT was modeled using the pseudo-first order, the pseudo-second order, and intraparticle diffusion kinetics equations. The results indicate that the pseudo-second order kinetic equation and intraparticle diffusion model were adequate to describe the adsorption kinetics.

Mathematical Modelling for Copper and Lead Adsorption on Coffee Grounds

2017 ◽  
Author(s):  
Jurgita Seniūnaitė ◽  
Rasa Vaiškūnaitė ◽  
Kristina Bazienė
Keyword(s):  
Heavy Metals ◽  
Mathematical Modelling ◽  
Adsorption Kinetics ◽  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Coffee Grounds ◽  
Pseudo Second Order

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.

scholarly journals Fast and Highly Efficient Adsorption Removal of Toxic Pb(II) by a Reusable Porous Semi-IPN Hydrogel Based on Alginate and Poly(Vinyl Alcohol)

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenbo Wang ◽  
Xiangyu Liu ◽  
Xue Wang ◽  
Li Zong ◽  
Yuru Kang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Kinetics ◽  
Vinyl Alcohol ◽  
Gel Strength ◽  
Second Order ◽  
Polymerization Reaction ◽  
Sodium Acrylate ◽  
Poly Vinyl Alcohol ◽  
Order Kinetic ◽  
Pseudo Second Order

A porous semi-interpenetrating network (semi-IPN) hydrogel adsorbent with excellent adsorption properties and removal efficiency towards Pb(II) was prepared by a facile grafting polymerization reaction in aqueous medium using natural biopolymer sodium alginate (SA) as the main chains, sodium acrylate (NaA) as the monomers, and poly(vinyl alcohol) (PVA) as the semi-IPN component. FTIR, TGA and SEM analyses confirm that NaA monomers were grafted onto the macromolecular chains of SA, and PVA chains were interpenetrated and entangled with the crosslinked network. The incorporation of PVA facilitates to form pores on the surface of hydrogel adsorbent. The semi-IPN hydrogel containing 2 wt% of PVA exhibits high adsorption capacity and fast adsorption rate for Pb(II). The best adsorption capacity reaches 784.97 mg/g, and the optimal removal rate reaches 98.39% (adsorbent dosage, 2 g/L). In addition, the incorporation of PVA improved the gel strength of hydrogel, and the storage modulus of hydrogel increased by 19.4% after incorporating 2 wt% of PVA. The increase of gel strength facilitates to improve the reusability of hydrogel. After 5 times of regeneration, the adsorption capacity of SA-g-PNaA decreased by 23.2%, while the adsorption capacity of semi-IPN hydrogel only decreased by 10.8%. The adsorption kinetics of the hydrogel in the initial stage (the moment when the adsorbent contacts solution) and the second stage are fitted by segmentation. It is intriguing that the adsorption kinetics fits well with both pseudo-second-order kinetic model and pseudo-first-order model before 60 s, while only fits well with pseudo-second-order adsorption model in the whole adsorption process. The chemical complexing adsorption mainly contribute to the efficient capturing of Pb(II).

scholarly journals Polyvinyl Alcohol/Calcium Carbonate Nanocomposites as Efficient and Cost-Effective Cationic Dye Adsorbents

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2179
Author(s):  
Davoud Jahani ◽  
Amin Nazari ◽  
Jaber Ghourbanpour ◽  
Amir Ameli
Keyword(s):  
Calcium Carbonate ◽  
Polyvinyl Alcohol ◽  
Adsorption Kinetics ◽  
Dye Removal ◽  
Dye Adsorption ◽  
Second Order ◽  
Order Kinetic ◽  
Cationic Dye ◽  
Intraparticle Diffusion Model ◽  
Pseudo Second Order

A novel polyvinyl alcohol (PVA)/calcium carbonate-based double-layer cationic dye adsorbent was developed. Polyvinyl alcohol (50 wt %) and calcium carbonate (50 wt %) were used together with borax as a cross-linking agent. The nanocomposite was prepared using only water, without the need for any toxic solvent or hazardous chemical. The final samples were obtained by the solvent casting method. The nanocomposite adsorbent was characterized using a Fourier transform infrared (FTIR) spectroscope and a scanning electron microscope (SEM). The adsorption performance on two cationic dyes, i.e., methylene blue and safranin was studied. Dye adsorption was quantified by measuring the nanocomposite swelling, contact time, and dye concentration. Pseudo first-order and pseudo second-order kinetic models as well as intraparticle diffusion model were used to model the adsorption kinetics. Moreover, the isotherm dye adsorption was investigated by Langmuir and Freundlich models. The results revealed that the developed nanocomposite has relatively high adsorption efficiency and short adsorption time and retains its performance after several successive absorption–desorption processes. The results also showed that the pseudo-second-order model best describes the adsorption kinetics, and the Freundlich isotherm model has a better compatibility with the experimental data. Finally, an adsorption mechanism was proposed for the dye removal process. The developed PVA/CaCO3 nanocomposite can be potentially used for efficient dye removal in wastewater treatments.

scholarly journals Carbonized Lanthanum-Based Metal-Organic Framework with Parallel Arranged Channels for Azo-Dye Adsorption

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1053
Author(s):  
Krzysztof Cendrowski ◽  
Karolina Opała ◽  
Ewa Mijowska
Keyword(s):  
Kinetic Model ◽  
Adsorption Kinetics ◽  
Hydrophobic Interactions ◽  
Metal Organic Framework ◽  
Second Order ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Metal Organic ◽  
Pseudo Second Order ◽  
Organic Framework

In this contribution, the synthesis of the metal−organic framework (MOF) based on lanthanum that exhibits trigonal prism shape is presented. The length of a single side of this structure ranges from 2 to 10 μm. The carbonized lanthanum-based organic framework (CMOF–La) maintained the original shape. However, the lanthanum oxide was reshaped in the form of rods during the carbonization. It resulted in the creation of parallel arranged channels. The unique structure of the carbonized structure motivated us to reveal its adsorption performance. Therefore, the adsorption kinetics of acid red 18 onto a carbonized metal−organic framework were conducted. Various physicochemical parameters such as initial dye concentration and pH of dye solution were investigated in an adsorption process. The adsorption was found to decrease with an increase in initial dye concentration. In addition, the increase in adsorption capacity was noticed when the solution was changed to basic. Optimal conditions were obtained at a low pH. Kinetic adsorption data were analyzed using the pseudo-first-order kinetic model, the pseudo-second-order kinetic model and the intraparticle diffusion model. The adsorption kinetics were well fitted using a pseudo-second-order kinetic model. It was found that the adsorption of anionic dye onto CMOF–La occurs by hydrophobic interactions between carbonized metal-organic framework and acid red 18.

Experimental Investigation on Adsorptive Removal of Phenolic Compounds from Aqueous Solution by Cr-Bentonite

2010 ◽  
Vol 160-162 ◽  
pp. 163-170
Author(s):  
Hong Zheng ◽  
Yang Wang ◽  
Peng Liang ◽  
Hong Bin Qi
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Phenolic Compounds ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Synthetic Wastewater ◽  
Order Kinetic ◽  
Sorption Data ◽  
Adsorptive Removal ◽  
Pseudo Second Order

The ability of Cr-bentonite prepared using synthetic wastewater containing chromium was investigated for adsorptive removal of 4-aminophenol and 4-chlorophenol from aqueous solution in a batch system at 25 °C. The physic-chemical parameters including pH value of solution and contact time were studied. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of sorption. The equilibrium sorption data for 4-aminophenol and 4-chlorophenol were well fitted to Langmuir adsorption isotherm and the monolayer sorption capacity was found to be 26.53 and 23.81 mg/g at 25 °C, respectively. The sorption energy calculated from Dubinin-Redushkevich (D-R) isotherm are 8.31 and 8.20 kJ/mol for the uptake of 4-aminophenol and 4-chlorophenol respectively which indicates that both the sorption processes are chemical in nature. The kinetic data were analyzed using pseudo-first order, pseudo-second order kinetic equation and intraparticle diffusion model. The experimental data fit very well the pseudo-second order kinetic model. Intraparticle diffusion affects 4-aminophenol and 4-chlorophenol uptake. Sorption studies carried out using industrial wastewater samples containing phenolic compounds show that there is significant potential for Cr-bentonite as an adsorbent material for phenollic compounds removal from aqueous solutions.

scholarly journals Glycidyl methacrylate macroporous copolymer grafted with diethylene triamine as sorbent for Reactive Black 5

2014 ◽  
Vol 68 (6) ◽  
pp. 685-699 ◽  
Author(s):  
Zvjezdana Sandic ◽  
Marija Zunic ◽  
Danijela Maksin ◽  
Aleksandra Milutinovic-Nikolic ◽  
Aleksandar Popovic ◽  
...  
Keyword(s):  
Glycidyl Methacrylate ◽  
Dye Removal ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Operating Conditions ◽  
Homogeneous Distribution ◽  
Reactive Black 5 ◽  
Order Kinetic ◽  
Diethylene Triamine ◽  
Pseudo Second Order

In this paper, macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine [PGME-deta], was evaluated as Reactive Black 5 (RB5) sorbent. Batch RB5 removal from aqueous solution by PGME-deta was investigated by varying pH, contact time, sorbent dosage, initial dye concentration and temperature. The sorption is pH sensitive having maximum at pH 2 (dye removal of 85%), decreasing with the increase of pH (dye removal of 24% at pH=11) after 60 min. Sorption kinetics was fitted to chemical-reaction and particle-diffusion models (pseudo-first-order, pseudo-second-order, intraparticle diffusion and Mckay models). The pseudo-second-order kinetic model accurately predicted the RB5 amount sorbed under all investigated operating conditions, while the intraparticle diffusion was the dominant rate-limiting mechanism. The diffusion mechanism was more prevalent with the decrease in temperature and the increase in concentration. The isotherm data was best fitted with the Langmuir model, indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption, with the maximum sorption capacity of 353 mg g-1. The calculated sorption rates improved with increasing temperature and an activation energy close to 40 kJ mol-1 was determined, suggesting that chemisorption was also rate-controlling.

scholarly journals Design of Hybrid PAH Nanoadsorbents by Surface Functionalization of ZrO2 Nanoparticles with Phosphonic Acids

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 952
Author(s):  
Nadine Bou Orm ◽  
Thomas Gréa ◽  
Marwa Hamandi ◽  
Alexandre Lambert ◽  
Florent Lafay ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Modification ◽  
Adsorption Kinetics ◽  
Surface Functionalization ◽  
Solid Phase ◽  
Nanocomposite Materials ◽  
Second Order ◽  
Order Kinetic ◽  
Phosphonic Acids ◽  
Pseudo Second Order

This study focuses on the preparation of innovative nanocomposite materials based on surface modification of commercial nano-ZrO2 optimized from Brønsted acid–base surface reactions. This surface modification was carried out by direct grafting of suitable phosphonic acids bearing a vinylic or phenylic substituent in aqueous solution. Different loading quantities of the anchoring organophosphorus compounds were applied for each materials synthesis. The resulting nanohybrids were thoroughly characterized by infrared spectroscopy (DRIFT), solid-state nuclear magnetic resonance (NMR), nitrogen adsorption-desorption (BET), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS), demonstrating the reliability and efficient tunability of the surface functionalization based on the starting Zr/P ratio. Our nanocomposite materials exhibited a high specific surface area as well as complex porosity networks with well-defined meso-pore. The as-prepared materials were investigated for the adsorption of a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) at 200 ng·mL−1 in an aqueous solution. Adsorption kinetics experiments of each individual material were carried out on the prepared PAHs standard solution for a contact time of up to 6 h. Pretreatments of the adsorption test samples were performed by solid-phase extraction (SPE), and the resulting samples were analyzed using an ultrasensitive GC-orbitrap-MS system. The pseudo-first-order and the pseudo-second-order models were used to determine the kinetic data. The adsorption kinetics were best described and fitted by the pseudo-second-order kinetic model. The correlation between the nature of the substituent (vinylic or phenylic) and the parameters characterizing the adsorption process were found. In addition, an increase of PAHs adsorption rates with phosphonic acid loading was observed.

scholarly journals Activated Carbon Derived From OPEFB by One Step Steam Activation and Its Application for Dye Adsorption : Kinetics and Isothermal Studies

REAKTOR ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 68-76
Author(s):  
Fahriya Puspita Sari ◽  
Dede Heri Yuli Yanto ◽  
Gustan Pari
Keyword(s):  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Adsorption Process ◽  
Second Order ◽  
Order Kinetic ◽  
Activated Carbon Adsorption ◽  
Steam Activation ◽  
Carbon Adsorption ◽  
Pseudo Second Order ◽  
One Step

Activated carbon was prepared from OPEFB by one step steam activation method. The adsorption performance for the removal of acid orange 52 (AO 52), reactive blue 19 (RB 19), basic violet 1 (BV 1) was investigated. Each dye has a different chemical structure such as azoic, anthraquinone, triarylmethane for AO 52, RB 19, and BV 1 respectively. The effects of adsorbent dosage, pH, and contact time on the adsorption process were studied. Experimental data were analyzed by model equations such as Langmuir, Freundlich and Temkin isotherms and it was found that the Langmuir isotherm model best fitted for all three dyes with R2 values is higher than 0.95. Langmuir model assumes a homogeneous nature and monolayer coverage of dye molecules at the outer surface of activated carbon. Adsorption kinetics was determined using pseudo-first-order, pseudo-second-order rate equations, Elovich model and also intraparticle diffusion models. Kinetic studies showed that the pseudo-second-order kinetic model better described the adsorption process with R2 values exceeds 0,99 compared with the other kinetics model. The SEM images showed AC pores was well developed with steam activation while wider porosity is created in the macropore range. FT-IR analysis had shown that the AC functional groups were disappeared because of vaporization the volatile materials when the heating process. Keywords: Activated Carbon, Adsorption Isotherms, Kinetic, OPEFB, Steam Activation

scholarly journals Sorption Profile of Phosphorus Ions onto ZnO Nanorods Synthesized via Sonic Technique

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
M. F. Elkady ◽  
H. Shokry Hassan ◽  
Eslam Salama
Keyword(s):  
Zinc Oxide ◽  
Surface Area ◽  
High Efficiency ◽  
Zno Nanorods ◽  
Intraparticle Diffusion ◽  
Second Order ◽  
Oxide Material ◽  
Order Kinetic ◽  
Phosphorus Sorption ◽  
Pseudo Second Order

High surface area zinc oxide material in nanorod morphological structure was synthesized using an ultrasonic technique in the presence of polyvinyl pyrrolidone as stabilizing agent. The crystallite, morphology, and surface area of the prepared white powder material were identified using XRD, SEM, and BET techniques, respectively. X-ray analysis confirms the high purity of synthesized ZnO. The evaluated specific surface area of prepared ZnO was 16.7 m2/g; this value guarantees high efficiency for water purification. The feasibility of synthesized ZnO nanorods for phosphorus sorption from aqueous solution was established using batch technique. Nano-zinc oxide exhibits high efficiency for phosphorus removal; the equilibrium state was recorded within 90 minutes. The most effective hydrogen ion concentration of the polluted solution was recorded at pH = 1 for phosphorus decontamination. The equilibrium of phosphorus sorption onto ZnO nanorods was well explained using both Langmuir and Temkin isotherm models. The calculated maximum monolayer sorption capacity was 89 mg/g according to Langmuir isotherm at 27°C. In order to explain the phosphorus sorption mechanism onto the prepared ZnO nanorods, three simplified kinetic models of pseudo-first order, pseudo-second order, and intraparticle diffusion rate models were tested. Kinetics was well fitted by pseudo-second order kinetic model with a contribution of intraparticle diffusion.

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