scholarly journals Preparation of new diatomite–chitosan composite materials and their adsorption properties and mechanism of Hg(II)

2017 ◽  
Vol 4 (12) ◽  
pp. 170829 ◽  
Author(s):  
Yong Fu ◽  
Xiaoxu Xu ◽  
Yue Huang ◽  
Jianshe Hu ◽  
Qifan Chen ◽  
...  
Keyword(s):  
Adsorption Isotherm ◽  
Kinetic Model ◽  
Contact Time ◽  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Order Kinetic Model

A new composite absorbent with multifunctional and environmental-friendly structures was prepared using chitosan, diatomite and polyvinyl alcohol as the raw materials, and glutaraldehyde as a cross-linking agent. The structure and morphology of the composite absorbent, and its adsorption properties of Hg(II) in water were characterized with Fourier transform infrared (FT-IR) spectra, scanning electron microscope (SEM), X-ray diffraction (XRD), Brunauer Emmett Teller (BET) measurements and ultraviolet–visible (UV–Vis) spectra. The effect of the pH value and contact time on the removal rate and absorbance of Hg(II) was discussed. The adsorption kinetic model and static adsorption isotherm and regeneration of the obtained composite absorbent were investigated. The results indicated that the removal of Hg(II) on the composite absorbent followed a rapid adsorption for 50 min, and was close to the adsorption saturation after 1 h, which is in accord with the Langmuir adsorption isotherm model and the pseudo-second-order kinetic model. When the pH value, contact time and the mass of the composite absorbent was 3, 1 h and 100 mg, respectively, the removal rate of Hg(II) on the composite absorbent reached 77%, and the maximum adsorption capacity of Hg(II) reached 195.7 mg g −1 .

scholarly journals Preparation of chitosan/amine modified diatomite composites and adsorption properties of Hg(II) ions

2018 ◽  
Vol 77 (5) ◽  
pp. 1363-1371 ◽  
Author(s):  
Yong Fu ◽  
Yue Huang ◽  
Jianshe Hu ◽  
Zhengjie Zhang
Keyword(s):  
Schiff Base ◽  
Contact Time ◽  
Ph Value ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Effect ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Modified Diatomite

Abstract A green functional adsorbent (CAD) was prepared by Schiff base reaction of chitosan and amino-modified diatomite. The morphology, structure and adsorption properties of the CAD were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy and Brunauer Emmett Teller measurements. The effect of pH value, contact time and temperature on the adsorption of Hg(II) ions for the CAD is discussed in detail. The experimental results showed that the CAD had a large specific surface area and multifunctional groups such as amino, hydroxyl and Schiff base. The optimum adsorption effect was obtained when the pH value, temperature and contact time were 4, 25 °C and 120 min, respectively, and the corresponding maximum adsorption capacity of Hg(II) ions reached 102 mg/g. Moreover, the adsorption behavior of Hg(II) ions for the CAD followed the pseudo-second-order kinetic model and Langmuir model. The negative ΔG0 and ΔH0 suggested that the adsorption was a spontaneous exothermic process.

scholarly journals Removal of metronidazole antibiotic from aqueous solution by ammonia-modified activated carbon: adsorption isotherm and kinetic study

2021 ◽  
Author(s):  
Ali Ahmadfazeli ◽  
Yousef Poureshgh ◽  
Yousef Rashtbari ◽  
Hamed Akbari ◽  
Peyman Pourali ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Contact Time ◽  
Kinetic Studies ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Activated Carbon Adsorption ◽  
Modified Activated Carbon ◽  
Initial Ph ◽  
Order Kinetic Model

Abstract This article was aimed at investigating the removal of metronidazole (MNZ) from aquatic solutions by modified activated carbon (MAC) with amine groups. The effect of various parameters on the adsorption rate such as the initial pH, adsorbent dose and initial concentration of MNZ and contact time were scrutinized. MAC was characterized by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller techniques. The obtained results illustrated that under the optimum conditions (pH = 3, contact time = 50 min, initial MNZ concentration = 5 mg/L and MAC dose = 0.5 g/L), the maximum adsorption efficiency was 95%. Furthermore, the kinetic studies indicated the applicability of the pseudo-second-order kinetic model, whereas the adsorption isotherm fitted well with the Freundlich model (0.996), and the maximum adsorption capacity was 66.22 mg/g. The SBET and the total pure volume of MAC were 706.92 m2/g and 0.532 cm3/g, respectively. Also, the regeneration tests demonstrated that MAC had good stability after five cycles (73%). It can be concluded that MAC, as an effective adsorbent, has a high ability to remove MNZ from aqueous solutions.

scholarly journals Kinetic and Thermodynamic Adsorption of Cr(VI) onto Dried Oscillatoria Splendida in Aqueous Solution

2018 ◽  
Vol 3 (4) ◽  
pp. 195
Author(s):  
Risfidian Mohadi ◽  
Doni Setiawan ◽  
Hilda Zulkifli
Keyword(s):  
Aqueous Solution ◽  
Kinetic Model ◽  
Contact Time ◽  
Adsorption Properties ◽  
Ion Concentration ◽  
Order Kinetic ◽  
Adsorption Study ◽  
Batch System ◽  
Rate Of Reaction ◽  
Order Kinetic Model

Kinetic and thermodynamic adsorption study of Cr(VI) ion in aqueous solutions by dried Oscillatoria Splendida biomass was investigated in the batch system. The Oscillatoria Splendida was isolated and cultured from algae swamp ecosystem in South Sumatera. The adsorption properties of Cr(VI) onto dried Oscillatoria Splendida biomass was studied by the influences of contact time, initial Cr(VI) ion concentration and temperature of reaction. The experimental results were the rate of adsorption followed the second-order kinetic model with the rate of reaction k2 is 0.00181 mg g-1 min-1 and the adsorption thermodynamic agree to the Langmuir’s model with amount of  Cr(VI) removed from aqueous solution increased with increasing  Cr(VI) concentration with the higher adsorption energy was 8.46 kJ/mol at 50 °C.

Extraction of Heavy Metals from Aqueous Medium by Husk Biomass: Adsorption Isotherm, Kinetic and Thermodynamic study

2019 ◽  
Vol 233 (2) ◽  
pp. 201-223 ◽  
Author(s):  
Khalida Naseem ◽  
Rahila Huma ◽  
Aiman Shahbaz ◽  
Jawaria Jamal ◽  
Muhammad Zia Ur Rehman ◽  
...  
Keyword(s):  
Metal Ions ◽  
Aqueous Medium ◽  
Contact Time ◽  
Metal Ion ◽  
Adsorption Process ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Adsorption Sites ◽  
Order Kinetic Model

Abstract This study describes the adsorption of Cu (II), Co (II) and Ni (II) ions from wastewater on Vigna radiata husk biomass. The ability of adsorbent to capture the metal ions has been found to be in the order of Ni (II)>Co (II) and Cu (II) depending upon the size and nature of metal ions to be adsorbed. It has been observed that percentage removal of Cu (II), Co (II) and Ni (II) ions increases with increase of adsorbent dosage, contact time and pH of the medium but up to a certain extent. Maximum adsorption capacity (qmax) for Cu (II), Co (II) and Ni (II) ions has been found to be 11.05, 15.04 and 19.88 mg/g, respectively, under optimum conditions of adsorbent dosage, contact time and pH of the medium. Langmuir model best fits the adsorption process with R2 value approaches to unity for all metal ions as compared to other models because adsorption sites are seemed to be equivalent and only monolayer adsorption may occur as a result of binding of metal ion with a functional moiety of adsorbent. Pseudo second order kinetic model best interprets the adsorption process of Cu (II), Co (II) and Ni (II) ions. Thermodynamic parameters such as negative value of Gibbs energy (∆G°) gives information about feasibility and spontaneity of the process. Adsorption process was found to be endothermic for Cu (II) ions while exothermic for Co (II) and Ni (II) ions as signified by the value of enthalpy change (∆H°). Husk biomass was recycled three times for removal of Ni (II) from aqueous medium to investigate its recoverability and reusability. Moreover V. radiata husk biomass has a potential to extract Cu (II) and Ni (II) from electroplating wastewater to overcome the industrial waste water pollution.

Adsorption of Pb(II) from Aqueous Solutions on Dithizone-Immobilized Coal Fly Ash

2020 ◽  
Vol 840 ◽  
pp. 57-63
Author(s):  
Dina Fitriana ◽  
Mudasir Mudasir ◽  
Dwi Siswanta
Keyword(s):  
Fly Ash ◽  
Adsorption Isotherm ◽  
Contact Time ◽  
Coal Fly Ash ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Activated Coal ◽  
Concentration Of Ions ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Adsorption of Pb(II) ions onto selective adsorbent of dithizone-immobilized coal fly ash (DCFA) from Holcim, Cilacap, Indonesia has been investigated in batch experiments. Prepared coal fly ash (CFA) modified by immobilization of dithizone previously were characterized by FT-IR and XRD. Several parameters influencing the adsorption of Pb(II) ions such as effect of pH, adsorbent dosage, contact time and initial concentration of ions on the efficiency of the adsorption were studied. The optimum condition of Pb(II) adsorption was found at pH 5, adsorbent dosage 0.1 g, contact time 60 min and initial Pb(II) ions concentration of 60 mg L–1. The adsorption kinetics of Pb(II) ions on DCFA was found to follow a pseudo-second-order kinetic model. The adsorption isotherm data were fitted to the Langmuir model. Kinetics and adsorption isotherm studies suggest that the capacity and affinity of the DCFA in adsorbing Pb(II) ions is significantly improved compared to those of non-immobilized activated coal fly ash (ACFA).

Utilization of cross-linked chitosan/bentonite composite in the removal of methyl orange from aqueous solution

2014 ◽  
Vol 71 (2) ◽  
pp. 174-182 ◽  
Author(s):  
Ruihua Huang ◽  
Qian Liu ◽  
Lujie Zhang ◽  
Bingchao Yang
Keyword(s):  
Methyl Orange ◽  
Aqueous Solutions ◽  
Ph Value ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Wide Ph Range ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Ph Range ◽  
A Minor

A kind of biocomposite was prepared by the intercalation of chitosan in bentonite and the cross-linking reaction of chitosan with glutaraldehyde, which was referred to as cross-linked chitosan/bentonite (CCS/BT) composite. Adsorptive removal of methyl orange (MO) from aqueous solutions was investigated by batch method. The adsorption of MO onto CCS/BT composite was affected by the ratio of chitosan to BT and contact time. pH value had only a minor impact on MO adsorption in a wide pH range. Adsorption kinetics was mainly controlled by the pseudo-second-order kinetic model. The adsorption of MO onto CCS/BT composite followed the Langmuir isotherm model, and the maximum adsorption capacity of CCS/BT composite calculated by the Langmuir model was 224.8 mg/g. Experimental results indicated that this adsorbent had a potential for the removal of MO from aqueous solutions.

scholarly journals Fluoride adsorption properties of three modified forms of activated alumina in drinking water

2014 ◽  
Vol 12 (4) ◽  
pp. 715-721 ◽  
Author(s):  
Ying Duan ◽  
Chenchen Wang ◽  
Xuede Li ◽  
Wei Xu
Keyword(s):  
Drinking Water ◽  
Surface Area ◽  
Adsorption Properties ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Activated Alumina ◽  
Fluoride Ions ◽  
Fluoride Adsorption ◽  
Order Kinetic Model ◽  
Chlorine Ions

The study describes the removal of fluoride from drinking water using activated alumina (AA). AA was modified with H2SO4, FeCl3 and a combination of the two to enhance fluoride adsorption. The AA adsorbents were characterized using Brunauer–Emmett–Teller surface area analysis and X-ray fluorescence. The maximum adsorption capacity of H2SO4- and FeCl3-modified AA adsorbents was 4.98 mg/g, which is 3.4 times higher compared with that of normal AA. The results showed that the surface area of AA increased when modified with H2SO4. AA modified with FeCl3 enhanced fluoride adsorption ability through ion-exchange between chlorine ions and fluoride ions. The fluoride adsorption properties of AA modified with both H2SO4 and FeCl3 were consistent with the Langmuir model. The fluoride adsorption kinetics of the adsorbents were well described by the pseudo-second-order kinetic model.

Characteristics and kinetics of hexavalent chromium reduction by gallic acid in aqueous solutions

2015 ◽  
Vol 71 (11) ◽  
pp. 1694-1700 ◽  
Author(s):  
ZiFang Chen ◽  
YongSheng Zhao ◽  
Qin Li
Keyword(s):  
Kinetic Model ◽  
Gallic Acid ◽  
Hexavalent Chromium ◽  
Ph Value ◽  
Order Kinetic ◽  
First Order ◽  
Molar Ratios ◽  
Wide Range ◽  
Order Kinetic Model ◽  
Pseudo First Order

Gallic acid (GA) is a naturally occurring plant polyphenol compound. Experiments were conducted to study the kinetics and effects of pH, temperature, irradiation, and initial hexavalent chromium (Cr(VI)) concentration on Cr(VI) reduction by GA. Results indicated that Cr(VI) could be reduced to chromium oxide (Cr(III)) with GA in a wide range of pH values from 2.0 to 8.5. The reaction followed a pseudo-first-order kinetic model with respect to Cr(VI) and GA in acid conditions (pH 2.0–5.0). However, the reaction did not follow the pseudo-first-order kinetic model at pH 6.5 and 8.5. Removal efficiencies and reaction rate constants of Cr(VI) significantly increased with decreasing pH value and increasing temperature. The effect of irradiation on Cr(VI) reduction increased with increasing pH, and irradiation improved the removal efficiency of Cr(VI) by 11.29% at pH 6.5. At pH 2.0, nearly all molar ratios of GA required for the reduction of Cr(VI) were 1:2 (±0.1) under different initial Cr(VI) concentrations; however, the molar ratios of GA required for the reduction of Cr(VI) were 1:1.29, 1:1.43, and 1:1.69, respectively, when the initial Cr(VI) concentrations were 10, 25, and 50 mg/L at pH 5.5.

scholarly journals Development of Cerium Oxide/Corncob Nanocomposite: A Cost-Effective and Eco-Friendly Adsorbent for the Removal of Heavy Metals

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4464
Author(s):  
Sidra Gran ◽  
Rukhsanda Aziz ◽  
Muhammad Tariq Rafiq ◽  
Maryam Abbasi ◽  
Abdul Qayyum ◽  
...  
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Contact Time ◽  
Cost Effective ◽  
Particle Diffusion ◽  
Order Kinetic ◽  
Removal Of Heavy Metals ◽  
Intra Particle Diffusion ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This research aims to assess the efficiency of the synthesized corncob as a cost-effective and eco-friendly adsorbent for the removal of heavy metals. Therefore, to carry out the intended research project, initially, the corncob was doped with nanoparticles to increase its efficiency or adsorption capacity. The prepared adsorbent was evaluated for the adsorption of cadmium (Cd) and chromium (Cr) from aqueous media with the batch experiment method. Factors that affect the adsorption process are pH, initial concentration, contact time and adsorbent dose. The analysis of Cd and Cr was performed by using atomic absorption spectrometry (AAS), while the characterization of the adsorbent was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that there is a significant difference before and after corncob activation and doping with CeO2 nanoparticles. The maximum removal for both Cd and Cr was at a basic pH with a contact time of 60 min at 120 rpm, which is 95% for Cd and 88% for Cr, respectively. To analyze the experimental data, a pseudo-first-order kinetic model, pseudo-second-order kinetic model, and intra-particle diffusion model were used. The kinetic adsorption studies confirmed that the experimental data were best fitted with the pseudo-second-order kinetic model (R2 = 0.989) and intra-particle diffusion model (R2 = 0.979). This work demonstrates that the cerium oxide/corncob nanocomposite is an inexpensive and environmentally friendly adsorbent for the removal of Cd and Cr from wastewater.

scholarly journals A Fungal Modified Material With High Uranium (VI) Absorption Capacity And Strong Anti-Interference Ability

2022 ◽  
Author(s):  
Ni Tan ◽  
Qiaorong Ye ◽  
Yaqing Liu ◽  
Yincheng Yang ◽  
Zui Ding ◽  
...  
Keyword(s):  
Ph Value ◽  
Orthogonal Experiment ◽  
Target Material ◽  
Absorption Capacity ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Solid Liquid

Abstract With polydioxyethylene ether as the bridge chain, a new fungal modified material with diamidoxime groups was prepared by a series of uncomplex synthesis reaction. The orthogonal experiment obtained its optimized adsorption conditions as follows: the initial pH value 6.5, the initial uranyl concentration 40 mg L-1, the contact time 130 min, and the solid-liquid ratio 25 mg L-1. The maximum adsorption capacity of target material was 446.20 mg g-1, and it was much greater than that of the similar monoamidoxime material (295.48 mg g−1). The linear Langmuir (R2 = 0.9856) isotherm models and the linear pseudo-second-order kinetic model (R2 = 0.9931) fit the experimental data of uranium (VI) adsorption better, indicating the adsorption mechanism should mainly be the monolayer adsorption and chemical process. In addition, the relevant experiments exhibited the prepared material was of the good reuse and the excellent anti-interference performance, which suggested the new acquisition should also have well-applied prospect in the future.

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