Optimization of Cd(II) adsorption condition by glycine-modified silica-based adsorbent using central composite design

Silica gel (SG) is one of common adsorbent on solid phase extraction for preconcentration. Due to the low selectivity and effectiveness of adsorption to metal ions, SG should be modified. The SG was modified with d-glycine (Si-Gly) using 3-aminopropyltrimethoxysilane and glutaraldehyde as a crosslinker. Capability of Si-Gly as adsorbent for cadmium ions (Cd) was investigated using batch adsorption. The result was proved by infrared spectra. The optimum condition of Cd adsorption by the Si-Gly was obtained at pH 5, with 0.3 g of adsorbent and 11 minutes of contact time. The percentage of Cd adsorption at the optimum condition by the Si-Gly (99.34%) which is greater than the SG (89.03%). The maximum adsorption capacity of the Si-Gly is 9.77 mg/g, obtained at 400 mg/L. The Cd(II) adsorption on the SG and the Si-Gly follow the Langmuir isotherm equation.

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Effect of Pretreatment Methods on Enzymatic Kinetics of Ungelatinized Cassava Flour Hydrolysis

Catalysts ◽

10.3390/catal10070760 ◽

2020 ◽

Vol 10 (7) ◽

pp. 760

Author(s):

Tien Cuong Nguyen ◽

Son Chu-ky ◽

Hong Nga Luong ◽

Hai Van Nguyen

Keyword(s):

Solid Phase ◽

Glucose Production ◽

Enzyme Adsorption ◽

Cassava Flour ◽

Isotherm Equation ◽

Very High Gravity ◽

Hydrolysis Yield ◽

Langmuir Isotherm Equation ◽

Temperature Liquid ◽

Kinetics Of

The energy-saving glucose production process from starchy sources was developed by replacing high-temperature, liquid-phase by low-temperature, solid-phase. Therefore, the enzymatic hydrolysis under gelatinization temperature at very high gravity (≥300 g.L−1) of starchy substrates presents as an emerging technology. This study focused on the hydrolysis kinetics of cassava flour affected by different pretreatment methods. Cassava flour (dried, milled) was prepared in acetate buffer (pH 4.2) with starch concentration ranging from 10–30% (w/w). The mash was then pre-treated by three different methods for 30 min using heating (30, 40, 50 °C), enzyme (Viscozyme L 0.1% w/w) and microwave (3 × 20 s at 800 W). The suspension was then hydrolyzed with Stargen 002 (0.2% w/w) at 30 °C for 48 h. The enzyme adsorption kinetics was described by the Langmuir isotherm equation. The pretreatments at 50 °C and with enzyme resulted in the highest efficiency with the hydrolysis yield ranging from 76–79% after 48 h. The hydrolysis yield decreased to 67% (using microwave), 66% (at 45 °C), 61% (at 40 °C) and 59% (at 30 °C). The linear relationship between enzyme adsorption and produced glucose was demonstrated. The kinetics of glucose production was fitted by an empirical equation (analogy with Michaelis-Menten model) and allowed predicting the maximum hydrolysis yield.

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Fast and Effective Route for Removing Methylene Blue from Aqueous Solution by Using Red Mud-Activated Graphite Composites

Journal of Chemistry ◽

10.1155/2019/2858170 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7

Author(s):

Ha Xuan Linh ◽

Ngo Thi Thu ◽

Tran Quoc Toan ◽

Do Tra Huong ◽

Bui Thanh Giang ◽

...

Keyword(s):

Aqueous Solution ◽

Methylene Blue ◽

Red Mud ◽

Contact Time ◽

Electrochemical Activation ◽

Maximum Adsorption Capacity ◽

Graphite Composite ◽

Isotherm Equation ◽

Langmuir Isotherm Equation ◽

Graphite Composites

In this work, the mixture of red mud slurry and inorganic salt ((NH4)2SO4) has been used as an electrolyte for electrochemical activation of graphite. The red mud-activated graphite composite was then used as an adsorbent for removing methylene blue from aqueous solution by the batch method. The effect of pH, contact time, adsorbent dosage, and the initial concentration of methylene blue was investigated. The optimal condition was found at pH 6, contact time 120 min, and amount of adsorbent 1 mg/L. The maximum adsorption capacity was found to be 89.28 mg/g based on the Langmuir isotherm equation, suggesting that the red mud-activated graphite composite is a very potential adsorbent for removing methylene blue and is also used in other coloured wastewater treatments.

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Preparation and Chelating Properties of Polystyrene Modified Ethoxycarbonyl Thiourea Resin

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.781 ◽

2011 ◽

Vol 239-242 ◽

pp. 781-785 ◽

Cited By ~ 2

Author(s):

Shuai Wang ◽

Hong Zhong ◽

Liu Yin Xia ◽

Zhong Nan Wang ◽

Qian Zhang

Keyword(s):

Adsorption Isotherm ◽

Adsorption Capacity ◽

Maximum Adsorption Capacity ◽

Polymer Grafting ◽

Isotherm Equation ◽

Adsorption Capacities ◽

Adsorption Data ◽

Separation Factors ◽

Langmuir Isotherm Equation ◽

Freundlich Adsorption Isotherm

A novel polystyrene modified ethoxycarbonyl thiourea resin(PSETU) was synthesized by polymer grafting of aminated polystyrene and ethoxycarbonyl isothiocyanate. The adsorption capacities of PSETU follow the order: Au(III) > Cu(II) > Zn(II) > Ni(II) > Fe(III) > Ca(II) ≈ Mg(II). The adsorption capacity for Au(III) increases with the increase of contact time, temperature and initial concentration of Au(III). The adsorption data fit Boyd’s diffusion equation of liquid film, Langmuir adsorption isotherm and Freundlich adsorption isotherm. The maximum adsorption capacity of PSETU calculated by Langmuir isotherm equation is 3.485 mmol/g, and the separation factors of PSETU for Au(III)-base metal ions are above 380. According to XPS results, the functional atoms of PSETU coordinate with Au(III) during the adsorption process.

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MODEL ISOTERM FREUNDLICH DAN LANGMUIR OLEH ADSORBEN ARANG AKTIF BAMBU ANDONG (G. verticillata (Wild) Munro) DAN BAMBU ATER (G. atter (Hassk) Kurz ex Munro)

Jurnal Sains Natural ◽

10.31938/jsn.v2i1.31 ◽

2017 ◽

Vol 2 (1) ◽

pp. 17 ◽

Cited By ~ 1

Author(s):

Murtihapsari Murtihapsari ◽

Bertha Mangallo ◽

Dini Dwi Handyani

Keyword(s):

Adsorption Capacity ◽

Activated Charcoal ◽

Langmuir Isotherm ◽

Physical Adsorption ◽

Regression Coefficients ◽

Maximum Adsorption Capacity ◽

Optimum Conditions ◽

Isotherm Equation ◽

Freundlich Isotherms ◽

Langmuir Isotherm Equation

Freundlich and Langmuir Isotherms Model by Active Chorcoal Adsorbent Bamboo Andong (G. verticillata (Wild) Munro) and Bamboo Ater (G. atter (Hassk) Kurz ex Munro) Diazinon insecticide adsorption by two types of adsorbent, namely activated charcoal bamboo andong (G. verticillata (Wild) Munro) and bamboo ater (G. atter (Hassk) Kurzex Munro) at optimum conditions determined the maximum adsorption capacity of both types of adsorbent. Data analysison the effect of concentration on the adsorption capacity was used Langmuir and Freundlich isotherms equation. It was obtained. That the curve of adsorption isotherms of the Langmuir isotherm better modeled with linear regression coefficients were relatively more approach 1 is R2 = 0,996 for both types of adsorbents. Langmuir isotherm equation obtained from adsorpsi maximum capacity of activated charcoal bamboo andong (G. verticillata (Wild) Munro) of 4.630 mg/g (1,433.10-5 mol/g) with K = 0,332 (Kmol/L)-1 and Eads at -2,750 kJ/mol, while the activated charcoal bamboo ater (G. atter (Hassk) Kurzex Munro) produce the maximum adsorption capacity of 1,786 mg/g (5,868.10-6 mol/g) with K = 0,202 (Kmol/L)-1 and Eads = -3,898 kJ/mol, so the adsorption of both types of adsorbents indicated experiencing a physical adsorption (physisorption / fisisorpsi).Keyword: G. verticillata (Wild) Munro, G. atter (Hassk) Kurz ex Munro, Adsorption, Diazinon, actived charcoal ABSTRAK Adsorpsi insektisida diazinon oleh dua jenis adsorben, yaitu arang aktif bambu andong (G. verticillata (Wild) Munro) dan bambu ater (G. atter (Hassk) Kurz ex Munro) pada kondisi optimum bertujuan untuk menentukan kapasitas adsorpsi maksimum dari kedua jenis adsorben. Analisis data pengaruh konsentrasi terhadap kapasitas adsorpsi digunakan persamaan isoterm Langmuir dan Freundlich. Berdasarkan data yang diperoleh, kurva isoterm adsorpsi lebih mengikuti model isoterm Langmuir dengan koefisien regresi linier yang relatif lebih mendekati 1 yaitu R2 = 0,996 untuk kedua jenis adsorben. Dari persamaan isoterm Langmuir diperoleh kapasitas adsorpsi maksimum arang aktif bambu andong (G. verticillata (Wild) Munro) sebesar 4,630 mg/g (1,433.10-5 mol/g) dengan K = 0,332 (Kmol/L)-1 dan Eads sebesar -2,750 kJ/mol, sedangkan arang aktif bambu ater (G. atter (Hassk) Kurz ex Munro) menghasilkan kapasitas adsorpsi maksimum sebesar 1,786 mg/g (5,868.10-6 mol/g) dengan K = 0,202 (Kmol/L)-1 dan Eads = -3,898 kJ/mol, sehingga adsorpsi kedua jenis adsorben diindikasikan mengalami adsorpsi secara fisik (physisorption/ fisisorpsi).Kata kunci : G. verticillata (Wild) Munro, G. atter (Hassk) Kurz ex Munro Adsorpsi, Diazinon, Arang aktif

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Efficient removal of Malachite Green from aqueous solution by adsorption on carbon nanotubes modified with ZnFe2O4 nanoparticles

Journal of the Serbian Chemical Society ◽

10.2298/jsc181228038d ◽

2019 ◽

Vol 84 (7) ◽

pp. 701-712 ◽

Cited By ~ 1

Author(s):

Abkenar Dehghan ◽

Morassa Hassannezhad ◽

Morteza Hosseini ◽

Mohammad Ganjali

Keyword(s):

Carbon Nanotubes ◽

Malachite Green ◽

Separation Efficiency ◽

Solid Phase ◽

Aqueous Media ◽

Multiwall Carbon Nanotubes ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Order Kinetic Model

In this study, multiwall carbon nanotubes modified with spinel zinc ferrite nanoparticle (ZnFe2O4/MWCNTs) were used as a solid phase adsorbent for the removal of Malachite Green (MG) from aqueous media. The synthesized nanocomposite was characterized by different methods, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Batch adsorption experiments to determine the optimal adsorption conditions and different factors that influence the adsorption efficiency (i.e., pH, amount of adsorbent, contact time, and the initial concentration of MG) were also evaluated and optimized. The data were satisfactorily fitted to the Langmuir model and a maximum adsorption capacity of 116.2 mg g-1 was obtained at a pH of 7.5. In addition, adsorption kinetics studies were performed. The adsorption of the model dye (MG) was found to reach equilibrium after 60 min, following a pseudo-second-order kinetic model. Furthermore, an external magnetic field could easily separate the nanoparticles from water with a high separation efficiency.

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Kinetic Study on Phosphorus Adsorption, Phosphorus Desorption, Nitrification, and Denitrification by Using Mineralized Refuse

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.340.461 ◽

2011 ◽

Vol 340 ◽

pp. 461-466

Author(s):

Ding Long Li ◽

Jing Si Tian ◽

Hou Hu Zhang ◽

Yi Min Zhang ◽

Yue Xiang Gao

Keyword(s):

Adsorption Capacity ◽

Langmuir Isotherm ◽

Maximum Adsorption Capacity ◽

Phosphorus Adsorption ◽

K Value ◽

Isotherm Equation ◽

Zero Order Kinetics ◽

Langmuir Isotherm Equation ◽

Nitrification And Denitrification ◽

Phosphorus Desorption

The mineralized refuse has a well particle size distribution and is similar asirregularly polyhedron with the high contents of Fe, Al, and Ca, which might be thephosphorus pool. The absorption and desorption of phosphorus, nitrification, and denitrification in the mineralized refuse and clay has been investigated by using batch incubation, respectively. The variation of phosphorous adsorption in the mineralized refuse and clay is fitted the Langmuir isotherm equation. The maximum phosphorus adsorption capacity in the mineralized refuse calculated based on the Langmuir isotherm equation is 2914 mg kg-1. Both the maximum adsorption capacity and adsorption rate of phosphorus in the mineralized refuse are over 2.0-fold more than that of the clay. The desorption rate of phosphorus in the mineralized refuse is only about 30%. NH4+-N contents in the mineralized refuse samples fell from 129 mg N kg-1 to 83.0 mg N kg-1 within the first 24 h during the nitrification process. Accordingly, the NO3--N content in the mineralized increased from 137 mg N kg-1 to 170 mg N kg-1. While the decrease of NH4+-N contents and the increase of NO3--N contents in the clay was only 1/2 and 1/6 as large as in the mineralized refuse, respectively. During the denitrification process, the K-value of the fitted zero-order kinetics for NO3--N denitrification in the mineralized refuse was 6.5-fold higher than in the clay.

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Batch study, equilibrium and kinetics of adsorption of naphthalene using waste tyre rubber granules

Journal of Xenobiotics ◽

10.4081/xeno.2014.2264 ◽

2014 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Felix A. Aisien ◽

Andrew N. Amenaghawon ◽

Albert I. Adinkwuye

Keyword(s):

Contact Time ◽

Batch Adsorption ◽

Order Kinetic ◽

Kinetics Of Adsorption ◽

Isotherm Equation ◽

Operational Variables ◽

Langmuir Isotherm Equation ◽

Equilibrium And Kinetics ◽

Waste Tyre ◽

Kinetics Of

The potential use of waste tyre rubber granules (WTRG) for the batch adsorption of naphthalene from aqueous solutions was investigated. The effect of various operational variables such as contact time, initial naphthalene concentration, adsorbent dose, size of adsorbent particles, and temperature of solution on the adsorption capacity of WTRG was evaluated. The adsorption of naphthalene by WTRG was a fast kinetic process with an equilibrium contact time of 60 min. A low temperature (5°C), small adsorbent particle size (0.212 mm) and higher adsorbent dosage favored the adsorption process. Results of isotherm studies revealed that adsorption of naphthalene was best described by the Langmuir isotherm equation (R<sup>2</sup>=0.997) while the kinetics of the process was best described by the Lagergren pseudofirst order kinetic equation (R<sup>2</sup>=0.998). This study has demonstrated the suitability of WTRG for the removal of naphthalene from aqueous solution.

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A study on the removal of prednisone from aqueous solutions by adsorption onto a vegetal activated carbon

Water Science & Technology ◽

10.2166/wst.2018.515 ◽

2018 ◽

Vol 78 (11) ◽

pp. 2328-2337 ◽

Cited By ~ 1

Author(s):

Jéssica C. Zanette ◽

Márcia T. Veit ◽

Gilberto C. Gonçalves ◽

Soraya M. Palácio ◽

Fernando R. Scremin ◽

...

Keyword(s):

Experimental Data ◽

Activated Carbon ◽

Aqueous Solutions ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

Order Model ◽

Different Temperatures ◽

Increasing Temperature ◽

Central Composite ◽

Adsorbent Dose

Abstract This study evaluated the prednisone removal from aqueous solutions using adsorption by an activated carbon of vegetal origin (VAC). A central composite rotatable design (CCRD) and the response surface methodology (RSM) were used to verify the influence of the parameters: pH, adsorbent dose and prednisone concentration in a batch adsorption process. Among the analyzed parameters, only the adsorbent dose and the prednisone concentration were statistically significant (α = 0.05) and the critical values obtained were adsorbent dose: 1.87 g/L, pH 7.56 and prednisone concentration: 3.66 mg/L with 77.51% of prednisone removal by VAC. The kinetic study of the adsorption of prednisone reached the equilibrium in 4 h. The pseudo-first-order model described adequately the kinetics data behavior. The equilibrium experimental data obtained at different temperatures showed that the VAC has a maximum adsorption capacity of 18.04 mg/g at a temperature of 30 °C. The prednisone removal decreased by the increasing temperature and the Langmuir isotherm well described the experimental data (R² > 0.98). Thermodynamic results shown that the prednisone removal of aqueous solutions by VAC is spontaneous and favorable process.

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Cadmium Adsorption on HDTMA Modified Montmorillionite

The Journal of Engineering Research [TJER] ◽

10.24200/tjer.vol6iss1pp8-14 ◽

2009 ◽

Vol 6 (1) ◽

pp. 8 ◽

Cited By ~ 1

Author(s):

Mohd. Elmuntasir I. Ahmed

Keyword(s):

Exchange Capacity ◽

Batch Adsorption ◽

Cadmium Removal ◽

Surface Precipitation ◽

Isotherm Equation ◽

Modified Montmorillonite ◽

Adsorption Capacities ◽

Langmuir Isotherm Equation ◽

High Concentrations ◽

Monolayer Coverage

In this paper the possibility of cadmium removal from aqueous solutions by adsorption onto modified montmorillonite clay is investigated. Batch adsorption experiments performed revealed an enhanced removal of cadmium using HDTMA modified montmorillonite to 100% of its exchange capacity. Modified montmorillonite adsorption capacity increases at higher pHs suggesting adsorption occurs as a result of surface precipitation and HDTMA complex formation due to the fact that the original negatively charged montmorillonite is now covered by a cationic layer of HDTMA. Adsorption isotherms generated followed a Langmuir isotherm equation possibly indicating a monolayer coverage. Adsorption capacities of up to 49 mg/g and removals greater than 90% were achieved. Anionic selectivity of the HDTMA modified monmorillonite is particularly advantageous in water treatment applications where high concentrations of less adsorbable species are present, and the lack of organoclay affinity for these species may allow the available capacity to be utilized selectively by the targeted species.

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Magnetic alginate beads with high basic dye removal potential and excellent regeneration ability

Canadian Journal of Chemistry ◽

10.1139/cjc-2016-0641 ◽

2017 ◽

Vol 95 (8) ◽

pp. 807-815 ◽

Cited By ~ 28

Author(s):

K.Z. Elwakeel ◽

A.A. El-Bindary ◽

A.Z. El-Sonbati ◽

A.R. Hawas

Keyword(s):

Langmuir Isotherm ◽

Alginate Beads ◽

Second Order ◽

Regeneration Ability ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Isotherm Equation ◽

Langmuir Isotherm Equation ◽

Order Kinetic Model ◽

Pseudo Second Order

The adsorption of crystal violet (CV) dye onto magnetic alginate (MAlg) composite from aqueous solutions was studied. Experiments were carried out as function of contact time, dosage, temperature, pH, and CV concentration in the solutions. Optimum CV uptake was observed at equilibrium pH 7 and most of the CV was sorbed within 30 min. The equilibrium adsorption data were analyzed using two common adsorption models: Langmuir and Freundlich. The results revealed that Langmuir isotherm fit the experimental results well. The maximum adsorption capacity obtained from Langmuir isotherm equation was 0.113 mmol g−1 at 298 ± 1 K. The kinetics adsorption of CV onto MAlg composite was investigated using the pseudo first-order and pseudo second-order kinetic models. The results showed that the adsorption of CV onto MAlg composite followed pseudo second-order kinetic model. Thermodynamic data indicated that the adsorption process is an endothermic and spontaneous reaction. Due to its outstanding adsorption capacities, MAlg composite is an excellent adsorbent for the removal of CV. The composite regeneration was greater than 98.6% with 0.01 mol/L HCl, and MAlg composite could be repeatedly utilized for CV removal with negligible loss in sorption capacity.

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