Modeling sorption isotherms of volatile organic chemical mixtures in model and natural solids
43
Citation
42
Reference
10
Related Paper
Citation Trend
Abstract:
Parameters from single-component isotherm models were used in multicomponent isotherm models to predict the aqueous phase sorption of trichloroethylene (TCE) in the presence of tetrachloroethylene (PCE) in four zeolites, Tenax, and three natural solids. The Langmuir, the Polanyi-Dubinin, and the Freundlich or the Langmuir-Freundlich isotherm models were used to simulate single-component sorption in zeolites. The Langmuir two-site, the Polanyi-Dubinin two-site, and the Freundlich or the Langmuir-Freundlich isotherm models were used to simulate single-component sorption in Tenax and natural solids. Two-site models have been used previously to model sorption in soils and sediments, and they combine an adsorption component (e.g., Langmuir) with a linear partitioning component. By using parameters from the different single-component isotherm models, the multicomponent Langmuir, the ideal adsorbed solution theory, and the Polanyi theory were each used to predict multicomponent sorption. In general, the ability to predict TCE sorption in the presence of PCE depended more on the choice of the single-component model than the multicomponent model, and better results were obtained when the Freundlich or the Langmuir-Freundlich isotherm was used for single-component sorption. This suggests that the more mechanistically based Langmuir and Polanyi-type models may not adequately describe the distribution of adsorption sites in some model and natural solids. The Freundlich or the Langmuir-Freundlich model, although empirical, has greater flexibility in characterizing sorbent heterogeneity and results in better multicomponent model predictions. However, this last statement is tenuous, because more solids must be tested against various model combinations.Keywords:
Langmuir adsorption model
Cite
Citations (65)
The adsorption of acid dyes by diatomite was investigated using Brilliant Scarlet 3R (NSK). Adsorption of this textile dyes onto diatomite earth sample was studied by batch adsorption techniques at varying temperatures 298 K, 309 K, 318 K, 328 K. The adsorption behavior of textile dye on diatomite samples was investigated using a UV-vis spectrophotometric technique. The adsorption processes follow the pseudo second-order model, and adsorption coverage over the surface of diatomite was studied using two well-known isotherm models: Langmuir's and Freundlich's. These results suggest that the dye adsorption isotherms fit well to Freundlich and Langmuir equation. The Freundlich equation 1/n between 0.3636 and 0.879 indicates favorable adsorption. The main driving forces of adsorption are electrostatic attraction and van der waals force. These results show that natural diatomite holds great potential to remove textile dyes from wastewater.
Textile
Cite
Citations (1)
It was reported that adsorption of bacteria (E.coli K12 and S.aureus) on anion exchange resins (SuperQ and DEAE). Adsorption isotherms of E.coli K12 and S.aureus on SuperQ and DEAE at 30℃ and 37℃ were measured by static state method. The adsorption isotherms were correlated with the Freundlichand the Langmuir equations,respectively.The results showed that the Freundlich equation was well fitted with adsorption isotherms and the correlation coefficients were between 0.991 and 0.995.The exponents of Freundlich isotherms were between 0.3 and 0.4. The amount adsorbed at 30℃ was more than that at 37℃.The effect of pH on the amount adsorbed was measured also by static state method. The results showed that when pH was between 2.0 and 5.0,the amount adsorbed about adsorption of E.coli K12 and S.aureus on SuperQ was less than that when pH was more than 6.0 and 7.0.
Ion-exchange resin
Cite
Citations (0)
Langmuir adsorption model
Caesium
Cite
Citations (13)
The boron (B) concentration in the soil solution is generally controlled by B adsorption and desorption reactions. With this background, a study was carried out to know the adsorption and desorption of boron using Freundlich, Langmuir and Temkin isotherms in cultivated soil of Himachal Pradesh. Eighty soil samples (0-0.15 m depth) were collected randomly from different locations across different districts of Himachal Pradesh and their B adsorption-desorption behaviour was studied. Among three different adsorption isotherms i.e. Freundlich, Langmuir and Temkin used to determine the B retention capacity of soils, Freundlich and Temkin isotherms represented better fit for fine textured soils, while Langmuir isotherm showed better fit for coarse textured soils. The results emanating from the study revealed that with increase in boron concentration, the boron adsorption by soils increases.
Cite
Citations (2)
In research carried out measurements of weight loss with API 5L grade B material in a solution of HCl 1 M. Extract Myrmecodia Pendans is used as a corrosion inhibitor. Immersion time was 2 hours, while the temperature variations used are 30, 40 and 50°C. Extracts of the ants 100-500 mg / L (multiples of 100 mg / L). In this study will also be analyzed with some models of adsorption mechanisms, including the Langmuir, Freundlich, and Temkin. This study aimed to determine the appropriate method of adsorption isotherms on each system. Adsorption equations of the model will be obtained values of free energy of a system. With the known value of free energy, it can be seen whether the adsorption occurs in physics or chemistry. This related to the surface protective layer formed on the surface absorption extract Myrmecodia Pendans. The results showed that the adsorption followed the Langmuir adsorption method at 30 and 40°C, while the temperature of 50°C followed Freundlich adsorption methods.
Cite
Citations (1)
The humic acid (HA), extracted from soils by alkali and acid was used to study the adsorption mechanism of Co2+, Cd2+. The results show that the best pH ranges from 6 to 7 and the adsorption procedure is exothermic reaction. The adsorption of Co2+ on HA fits for Langmuire and Freundlich adsorption equation, the amount of adsorption at the temperature of 19℃、 35℃、 45℃ are 12.51, 9.52, 8.30 mg/g respectively. The adsorption of Cd2+ on HA fits for Langmuire and Freundlich adsorption equation at the temperature of 19℃、 35℃, the amount of adsorption are 33.90, 33.30 mg/g respectively; however, at 45℃ it mainly fits for Freundlich adsorption equation. The adsorption of Co2+ ,Cd2+ on HA is in the way of forming complex compound through second order complex reaction.
Exothermic reaction
Cite
Citations (0)
Four adsorption equations were fitted to phosphate isotherm data for 38 soils from northern New South Wales. The two-surface Langmuir equation provided the best fit to the data. The Freundlich equation, however, was almost as effective, provided that an estimate of native adsorbed phosphate was included. It required fewer adsorption points because the transformed data produced a straight line. A regression constant, a, from the Freundlich equation although underestimating adsorption capacity, calculated from the Langmuir II equation, was highly correlated with this parameter (r = 0.984) and a buffering index (r = 0.986), calculated from the Langmuir I equation. The other Freundlich regression constant, n, was significantly correlated (P <1%) with the intensive parameters of adsorption from the one- and two-surface Langmuir equations. Since only two adsorption points are required for fitting the Freundlich equation and the parameters are easier to derive, it is suggested that this equation may be more suitable for commercial soil-testing laboratories than the Langmuir one- and two-surface equations for routine determination of phosphate adsorption characteristics of soils.
Langmuir equation
Cite
Citations (101)
The need to minimize surfactant adsorption on rock surfaces has been a challenge for surfactant-based, chemical-enhanced oil recovery (cEOR) techniques. Modeling of adsorption experimental data is very useful in estimating the extent of adsorption and, hence, optimizing the process. This paper presents a mini-review of surfactant adsorption isotherms, focusing on theories of adsorption and the most frequently used adsorption isotherm models. Two-step and four-region adsorption theories are well-known, with the former representing adsorption in two steps, while the latter distinguishes four regions in the adsorption isotherm. Langmuir and Freundlich are two-parameter adsorption isotherms that are widely used in cEOR studies. The Langmuir isotherm is applied to monolayer adsorption on homogeneous sites, whereas the Freundlich isotherm suites are applied to multilayer adsorption on heterogeneous sites. Some more complex adsorption isotherms are also discussed in this paper, such as Redlich-Peterson and Sips isotherms, both involve three parameters. This paper will help select and apply a suitable adsorption isotherm to experimental data.
Sorption isotherm
Langmuir adsorption model
Cite
Citations (546)
본 연구에서는 국내에서 대표적으로 버려지는 폐벌목 중 잣나무에서 만든 활성탄을 이용하여 벤젠에 대한 정지(static)흡착 실험을 수행하였다. 7.999 kPa에 이르는 압력 범위 내에서 온도 조건을 변화시켜 가며 303.15, 318.15, 333.15 K에서 흡착실험을 진행하였다. 등온흡착곡선은 Langmuir 등온흡착식, Freundlich 등온흡착식, Toth 등온흡착식을 적용하여 비교하였다. 벤젠의 흡착량(q)을 측정한 결과 Langmuir 등온흡착식과 Toth 등온흡착식으로 적용한 등온흡착곡선의 정확도가 높은 것으로 나타났다. 그리고 Langmuir 등온흡착식의 $q_{max}$ 값을 이용하여 흡착제의 흡착량을 비교하였다. 또한, 폐벌목 활성탄과 상용활성탄의 세공 발달 여부를 비교하기 위해 주사전자현미경(scanning electron microscopy, SEM) 사진을 관찰하였다. SEM 사진 관찰 결과, 폐벌목 활성탄이 국내 외 상용활성탄(DARCO A.C., SPG-100 A.C.)에 비해 세공발달 정도가 우수하며, 벤젠흡착량(q)이 높은 것을 확인할 수 있었다. 본 연구 결과를 통해 폐벌목 활성탄의 상용화 가능성을 검증할 수 있었다. In this study, experiments on the static adsorption of benzene were carried out using activated carbon made from Pinus koraiensis which is normally discarded waste timber in South Korea. The experiment were performed at 303.15 K, 318.15 K and 333.15 K under the pressure up to 7.999 kPa. Isothermal adsorption curves were obtained using Langmuir isotherm, Freundlich isotherm and Toth isotherm for comparison. Based on the fitting, the adsorption quantity of Benzene (q), the isothermal adsorption curves obtained from Langmuir isotherm and Toth isotherm showed the higher accuracy. Although there was little difference in accuracy between result from Langmuir isotherm and that from Toth isotherm, the adsorption quantity of Benzene (q) was expressed in terms of Langmuir isotherm because less parameters were required for Langmuir isotherm than for Toth isotherm. Moreover SEM images of the activated carbon from Pinus koraiensis and the commercial activated carbon were taken to observe the pore size development. The results showed that the perforation development of activated carbon from Pinus koraiensis (waste timber) was better than that of commercial activated carbon (DARCO A.C., SPG-100 A.C.). Adsorption quantity of benzene on activated carbon from Pinus koraiensis was confirmed to be higher than that on commercial activated carbon. Therefore, we may conclude that it is feasible to commercialize the process to manufacturing activated carbon from waste timber.
Langmuir adsorption model
Pinus koraiensis
Isothermal process
Cite
Citations (1)