Adsorption and recovery of nonylphenol ethoxylate on a crosslinked β-cyclodextrin-carboxymethylcellulose polymer

2010 ◽  
Vol 61 (9) ◽  
pp. 2293-2301 ◽  
Author(s):  
Danielle Bonenfant ◽  
Patrick Niquette ◽  
Murielle Mimeault ◽  
Robert Hausler

A study of adsorption/recovery of nonylphenol 9 mole ethoxylate (NP9EO) on a crosslinked β-cyclodextrin-carboxymethylcellulose (β-CD-CMC) polymer was carried out by ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopies. The adsorption was performed in mixtures containing 500 mg of the β-CD-CMC polymer and aqueous NP9EO solutions at concentrations 12–82 mg/L, whereas the recovery of NP9EO was effectuated by shaking the β-CD-CMC polymer loaded with methanol. The assays were made at 25°C and atmospheric pressure under agitation. The results have shown that the adsorption is a rapid process and the β-CD-CMC polymer exhibits a high NP9EO adsorption capacity of 83–92 w% (1.1–6.8 mg NP9EO/g β-CD-CMC polymer) dependent of the initial NP9EO concentration in liquid phase. This adsorption may involve the formation of an inclusion complex β-CD-NP9EO and a physical adsorption in the polymer network. The adsorption equilibrium measurements, which were analyzed using the Langmuir isotherm, have indicated a monolayer coverage and the homogeneous distribution of active sites at the surface of the β-CD-CMC polymer. Moreover, the negative value obtained for the free energy change (−13.2 kJ/mol) has indicated that the adsorption process is spontaneous. In parallel, the β-CD-CMC polymer exhibited a high NP9EO recovery efficiency of 97 w% that may occur through a decrease of binding strength between β-CD-CMC polymer and NP9EO. Together, these results suggest that the β-CD-CMC polymer could constitute a good adsorbent for removing nonylphenol ethoxylates from wastewater due to its high adsorption capacity and non-toxic character of β-CD and CMC to environment.

1999 ◽  
Vol 40 (7) ◽  
pp. 109-116 ◽  
Author(s):  
M. H. Ansari ◽  
A. M. Deshkar ◽  
P. S. Kelkar ◽  
D. M. Dharmadhikari ◽  
M. Z. Hasan ◽  
...  

Steamed Hoof Powder (SHP), size < 53μ, was observed to have high adsorption capacity for Hg(II) with >95% removal from a solution containing 100 mg/L of Hg(II) with only 0.1% (W/V) concentration of SHP. The SHP has good settling properties and gives clear and odour free effluent. Studies indicate that pH values between 2 and 10 have no effect on the adsorption of Hg(II) on SHP. Light metal ions like Na+, K+, Ca2+ and Mg2+ up to concentrations of 500 mg/L and heavy metals like Cu2+, Zn2+, Cd2+, Co2+, Pb2+, Ni2+, Mn2+, Cr3+, Cr6+, Fe2+ and Fe3+ up to concentrations of 100 mg/L do not interfere with the adsorption process. Anions like sulphate, acetate and phosphate up to concentrations of 200 mg/L do not interfere. Chloride interferes in the adsorption process when Hg(II) concentration is above 9.7 mg/L. The adsorption equilibrium was established within two hours. Studies indicate that adsorption occurs on the surface sites of the adsorbent.


2019 ◽  
Vol 6 (5) ◽  
pp. 182226 ◽  
Author(s):  
Jian Meng ◽  
Jianlan Cui ◽  
Siyuan Yu ◽  
Hui Jiang ◽  
Congshan Zhong ◽  
...  

Polyamine chelating adsorbents have a good removal effect on dye wastewater. In this study, small molecule triethylenetetramine and macromolecular poly(ethylene imine) were selected as aminated reagent, and two kinds of aminated chitosan microspheres, TETA-CTSms and PEI-CTSms, were obtained by emulsion cross-linking method. The microspheres were fully characterized by FTIR, SEM, XRD, EDS and TGA. EDS results showed that the N content of the PEI-CTSms and TETA-CTSms microspheres increased significantly after the cross-linking reaction and can reach 5.7 wt% and 7.3 wt%, respectively. Adsorption experiments confirmed that TETA-CTSms and PEI-CTSms showed greater adsorption characteristics for anionic dye reactive yellow (RY) in aqueous solutions compared with CTSms, and the adsorption capacity per unit area was increased by 39.11% and 88.56%, respectively. The adsorption capacity of aminated microspheres for RY decreased with the increase of pH. The adsorption kinetics conformed to the pseudo-second-order model, and the adsorption process was in accordance with the Langmuir isotherm model. The negative value of Δ G confirmed that the adsorption process was spontaneous, and the dye adsorption was a multiple process dominated by chemical chelating and physical adsorption.


2021 ◽  
Author(s):  
Yao He ◽  
huafeng tian ◽  
Aimin Xiang ◽  
Songbai Ma ◽  
Duoyuan Yin ◽  
...  

Abstract In recent years, the treatment of water pollution has been a challenging and far-reaching topic. In order to improve the adsorption performance of polyvinyl alcohol nanofibers, a new nano-adsorbent graphene oxide was introduced into them in this work. The introduction of GO greatly increases the adsorption of Cu2+, Methylene blue (MB) and Congo Red (CR). The adsorption kinetics and isotherm analysis of the PVA/GO nanofiber film during the adsorption process showed that the adsorption of Cu2+ and MB by PVA/GO nanofiber film was mainly chemical adsorption, while the adsorption of CR was mainly physical adsorption. The adsorption process of PVA/GO nanofiber film on Cu2+ was in line with the Langmuir isothermal adsorption model, that is, single molecular layer adsorption, the distribution of adsorption active sites was relatively uniform, and the increasing temperature was more conducive to the adsorption of Cu2+.


Author(s):  
Mansouri Taki Eddine Mohammed ◽  
Nibou Djamel ◽  
Trari Mohamed ◽  
Samira Amokrane

Abstract In this study, the microporous Metal Organic Framework-5 (MOF-5) has been synthesized to be used to remove methyl orange by adsorption. The adsorption experiments exhibit a good adsorption capacity at a catalyst dose of 0.1 g L−1 and for an initial concentration of 200 mg L−1, whereas the performance is stable over a wide pH range. The equilibrium adsorption data showed a sigmoidal course, which is well fitted by the Dubinin-Astakhov model applicable for physical adsorption processes (E = 0.055 kJ mol−1) onto heterogeneous surfaces and a more homogeneous pore structure (n = 9.9), with a maximum adsorption capacity of 1248.35 mg g−1. As can be observed from the evaluation of the kinetic data, the surface of the adsorbent is heterogeneous with different active sites for Methyl Orange (MO) adsorption. Moreover, based on the rate constant, it can be suggested that there is a specific interaction like electrostatic interaction between MO and the adsorbent for rapid and high uptake of the dye, whereas the adsorption phenomenon is reversible. According to the adsorption mechanisms, intra-particle and film diffusion models simultaneously controlled the rate sorption, which was confirmed by the calculated intra-particle diffusion and the film diffusion coefficients. The evaluation of the thermodynamic parameters revealed that the MO adsorption is spontaneous, endothermic and the randomness increases with the adsorption of MO.


Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 655 ◽  
Author(s):  
Xue-Qing Zhan ◽  
Fang-Chang Tsai ◽  
Lei Xie ◽  
Ke-Deng Zhang ◽  
Huan-Li Liu ◽  
...  

Isostructural zirconium-based metal–organic frameworks (Zr-MOFs) have attracted the attention of researchers because of their remarkable stability at high temperatures and high pressures and their chemical stabilities against acids and bases. Due to this stability, Zr-MOFs can be utilized in adsorption research, and the adsorption performance of a Zr-MOF depends on the pore size and the surroundings of the MOF. In this study, as the dimensions changed and the adsorption was carried out, the Zr-MOF material remained stable, and the adsorption of the best state was achieved at 235 mg/g. Through the simulation of theoretical kinetic models of Zr-MOFs, we initially postulated that the adsorption capacity is proportional to the pore size and that acid orange 7 (AO7) was adsorbed by the MOFs. Afterwards, we verified our hypotheses through a series of Brunauer–Emmett–Teller (BET) data analysis; non-local density function theory (NLDFT) was mainly used to analyze the data. Moreover, we determined that physical adsorption occurs on the surface of the MOFs during the adsorption process, while chemisorption occurs in the form of dye molecules combining with active sites. Ultimately, we concluded that the larger the pore size, the stronger the adsorption capacity, and this contribution casts a new light on the issue of wastewater treatment.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mohammed A. Saad ◽  
Mohammed J. Al-Marri ◽  
Ali L. Yaumi ◽  
Ibnelwaleed A. Hussein ◽  
Reyad Shawabkeh

A new CO2adsorbent is produced from waste oil fly ash (OFA). Ammonium hydroxide solution is used to convert OFA to activated carbon. Then, the product is used for the adsorption of CO2from a nitrogen/carbon dioxide (N2/CO2) gas mixture. The OFA samples are characterized by several techniques. Chemical treatment of OFA considerably changed its surface morphology. In particular, its surface area, as determined by BET measurements, increased from 59 to 318 m2/g. The amine-functionalized ash had a monolayer adsorption capacity of 74.51 mg/g and was obtained at relative pressure,0.05<p/ps<0.35. A kinetics study showed that the CO2adsorption capacity of OFA increased with increasing CO2flow rates and concentrations and decreasing the relative humidity. Unlike physical adsorption, the chemisorption process resulted in increased adsorption capacity with increasing temperatures over the range 0–40°C. We also found that the adsorption process was endothermic (80–173 kJ/mol). The isotherm data for the adsorption process were fitted using different models. The saturation capacity determined from the Sips model, which corresponds to the sum of the saturation capacities of all of the adsorbed layers, was 540.3 mg/g of ash.


2018 ◽  
Vol 36 (5-6) ◽  
pp. 1366-1385 ◽  
Author(s):  
Dunqiu Wang ◽  
Huijun Shan ◽  
Xiaojie Sun ◽  
Hongxia Zhang ◽  
Yanhua Wu

A sorbent was prepared by charring sugarcane bagasse (SCB) and used to remove nitrobenzene from aqueous solution. The surface area, morphology, and functional groups of the adsorbent were characterized by Brunauer–Emmett–Teller method, scanning electron microscopy, and Fourier transforms infrared spectroscopy. Analysis indicated that oxygen-containing functional groups, such as C = O, –OH, –COOH, and C–O–C, may be involved in the adsorption process. The adsorption of nitrobenzene was investigated under different operating conditions, including adsorbent dosage, initial nitrobenzene concentration, pH, and contact duration. Four kinetic models were applied to describe the adsorption process. Results revealed that the optimal sorbent mass was 0.3 g/50 mL at pH 5.8 and 25°C. The kinetic data obeyed the pseudo-second-order kinetic model ( R2 > 0.9965). In addition, Langmuir and Freundlich isotherm models were employed to describe the adsorption equilibrium. The Freundlich model presented better fitting for the adsorption equilibrium, suggesting that the carbonized SCB surface had a heterogeneous nature. The maximum adsorption capacities calculated by the Langmuir model were 38.27, 41.72, and 44.70 mg/g at 25°C, 35°C, and 45°C, respectively. The calculated values of ΔG0 and ΔH0 indicated the spontaneous and exothermic nature of the adsorption process at the considered temperature range. The adsorption mechanism of nitrobenzene onto carbonized SCB cannot be described either as physical adsorption or chemisorption. This study demonstrated that SCB biochar is a potential sorbent for removing nitrobenzene from aqueous solutions.


Author(s):  
Uwamungu ◽  
Nartey ◽  
Uwimpaye ◽  
Dong ◽  
Hu

The evaluation of biochar application on the adsorption behavior of topramezone on soil under no-tillage (NT) and rotary tillage treatments (RT) has been assessed. Fourier Transform Infra-Red Spectrometry (FTIR), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller) (BET) were used for the biochar characterization. Batch experiments were carried out in a laboratory to assess the adsorption of topramezone on soil through equilibrium and kinetic modeling under biochar addition. The clay content has been found to be higher under NT (18.24 ± 0.01) than under RT (15.91 ± 0.02). The total organic carbon was higher under NT. The topramezone adsorption equilibrium reached after 8 and 12 h, for NT and RT, respectively. The kinetic and thermodynamic analyses showed the adsorption under both treatments matched with pseudo-second-order kinetic and Langmuir models, respectively. After biochar addition, the pesticide adsorption capacity (40 < 25 < 15 °C) increased with decreasing temperature suggesting an exothermic adsorption process while negative values of Gibbs free energy (ΔG); −1848.07 and −366.531 J mol−1; for the soil under NT and RT at 25 °C, respectively, indicated spontaneous adsorption. Negative entropy values (ΔS); −21.92 and −78.296 J mol−1K−1, for NT and RT, respectively, explained a decreased randomness process. The enthalpy was higher (p < 0.05) under RT (−23,274.6 J mol−1) than under NT (−1313.73 J mol−1). Conclusively, it was shown that the topramezone adsorption capacity was higher under NT, and biochar addition increased more pesticide adsorption under NT than under RT.


2011 ◽  
Vol 399-401 ◽  
pp. 1191-1195
Author(s):  
Xiang Hao Wu ◽  
Shan Shan Yang ◽  
Cong Kai Zhang ◽  
Pan Yuan

The influence of the way and the volume of adding lime dust to fly ash-cement pastes on chloride physical adsorption capacity, chemical combination capacity and binding capacity of fly ash-cement pastes is investigated by adsorption equilibrium method. The results show that with the volume of lime dust as cement replacement raising, the amount of chloride physically adsorbed by fly ash-cement pastes reduces, while the amount of chloride chemical combining is firstly increase, and then decrease, and it reaches the maximum when the lime dust content is 10% , that of chloride binding is firstly increase, and then decrease, which reaches the maximum when the lime dust content is 5%. In addition, with the volume of lime dust as fly ash replacement increasing , the volume of chloride physically adsorbed by fly ash-cement pastes reduces firstly, and then raises, reaching the minimum when the lime dust content is 6%. Whereas, volume of chloride chemical combining and binding both decrease gradually with the increase of lime dust contents. When the population of lime dust as cement or fly ash replacement is low(less than 15% for cement and 9% for fly ash), effect of lime dust content on chloride binding capacity of fly ash-cement pastes is not obvious (under 7.5%).


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
M. Muhammad ◽  
Moonis Ali Khan ◽  
T. S. Y. Choong

Adsorption ofβ-carotene on mesoporous carbon coated monolith (MCCM) from methyl ester as a solvent was investigated. Kinetics and thermodynamics parameters have been evaluated. Maximumβ-carotene adsorption capacity was 22.37 mg/g at 50 °C. Process followed Langmuir isotherm. The adsorption was endothermic and spontaneous. Contact time studies showed increase in adsorption capacity with increase inβ-carotene initial concentration and temperature. Pseudo-second-order model was applicable to the experimental data. The value of activation energy confirmed physical adsorption process.


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