scholarly journals Regression Analysis for the Adsorption Isotherms of Betacyanin Extracts from the Dragon Fruit Peel onto the Spun Silk Yarn.

Author(s):  
Norasiha Hamid ◽  
Mimi Sakinah Abdul Munaim ◽  
Mazrul Nizam Abu Seman

The betacyanin pigment extracted from the dragon fruit peel has a potential to be a natural dye as an alternative to replace the synthetic dyes. To investigate the dyeability of spun silk with betacyanin pigment, the adsorption isotherm models were performed. The equilibrium adsorption data were analyzed using the Langmuir, Freundlich, and Temkin isotherm models. In order to determine the best-fit isotherm for each system, three error analysis methods were used to evaluate the data, namely the sum of the squares of the errors, residual root mean square error and chi-square test. On the basis of low three error analysis and high correlation of determination, it was found that the Langmuir isotherm model fitted well with the experimental data. Therefore, it can be concluded that the adsorption process of betacyanin pigment onto the spun silk followed the Langmuir isotherm model. Moreover, the adsorption features of the experimental system might be caused by the monolayer adsorption.

2007 ◽  
Vol 119 ◽  
pp. 303-306
Author(s):  
Y. Jung ◽  
Jei Won Yeon ◽  
Yeong Keong Ha

We present the preparation and Cu(II) adsorption characteristics of a new and innovative composite which was composed of a carboxymethylated polyethyleneimine (CM-PEI) and an activated carbon with a nanopore less than 2 nm in diameter. In this study, we examined the adsorption phenomena of Cu(II) on the CM-PEI/F400 composite and evaluated the adsorption data using three kinds of isotherm models (Langmuir, Freundlich, and Temkin isotherms). It was found that the adsorption of Cu(II) on the CM-PEI/F400 composite obeys the Langmuir isotherm model. Furthermore, The Cu element mapping results showed that Cu was well distributed throughout all the surface of the composite particle, suggesting that the surface of the F400 particle was uniformly covered with CM-PEI.


2022 ◽  
Vol 1212 (1) ◽  
pp. 012019
Author(s):  
I Syauqiah ◽  
D Nurandini ◽  
N P Prihatini ◽  
Jamiyaturrasidah

Abstract The process of manufacturing Sasirangan - a traditional fabric of South Kalimantan - has an impact that affects environmental pollution, namely the dyeing process of the fabric. The synthetic dyes used contain heavy metals and one of those toxic metals is copper (Cu). This study aims to determine the adsorption capacity of rice husk activated carbon adsorbent by adjusting the adsorption pattern based on isotherm models as the treatment to sasirangan liquid waste. The method consists of three stages: preparation of adsorbent by carbonization process, chemical and physical activation, then continued by adsorption process of Cu metal with carbon from rice husks with variations of adsorbent dose (2, 4, and 6 grams). This treatment was conducted by batch process. In this reseach, the adsorption capacity of rice husk adsorbent towards heavy metal Cu in sasirangan liquid waste was determined from the equilibrium state with the Langmuir isotherm equation and Freundlich isotherm equation. Based on isothermal studies of adsorption data, the correlation coefficient values obtained from the isotherm model approaches are: for dose of 2 grams adsorbent, Langmuir R2 = 0.9991 and Freundlich R2 = 0.9981; for dose of 4 grams adsorbent, Langmuir R2 = 0.9992 and Freundlich R2 = 0.9989; for dose of 6 grams adsorbent, Langmuir R2 = 0.9990 and Freundlich R2 = 0.9986. The results of investigation indicate that adsorption data correlated well with Langmuir isotherm model.


Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 398 ◽  
Author(s):  
Bandar R. M. Alsehli

UV-Vis spectrophotometer was used to determine chlorpropham (CIPC) concentration in aqueous solution. The method was validated in term of linearity, precision and limit of detection and limit of quantitation. The correlation coefficient of standards calibration curve of (1.0–10.0 µg/mL CIPC) was R2 = 1 with a precision (RSD%, n=10) ranged from (0.87–0.53%). The limit of detection (LOD) and limit of quantitation (LOQ) based on the regression statistics of the calibration curve data of (1.0–10.0 µg/mL CIPC) were 0.04 µg/mL and 0.11 µg/mL respectively. The activated carbon adsorbent was found to be effective for the removal approximately 80% of CIPC from aqueous solution. Several isotherm models (Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich) were evaluated. The maximum monolayer sorption capacity (Qm) from the Langmuir isotherm model was determined to be (44316.92 µg/g). The separation factor (RL) is 0.11 which indicates a favorable equilibrium sorption with the R2 value of 0.99, indicating that the Langmuir isotherm model fit the experimental sorption data well.


Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 942 ◽  
Author(s):  
Huo-Xi Jin ◽  
Hong Xu ◽  
Nan Wang ◽  
Li-Ye Yang ◽  
Yang-Guang Wang ◽  
...  

The ability to remove toxic heavy metals, such as Pb(II), from the environment is an important objective from both human-health and ecological perspectives. Herein, we describe the fabrication of a novel carboxymethylcellulose-coated metal organic material (MOF-5–CMC) adsorbent that removed lead ions from aqueous solutions. The adsorption material was characterized by Fourier-transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. We studied the functions of the contact time, pH, the original concentration of the Pb(II) solution, and adsorption temperature on adsorption capacity. MOF-5–CMC beads exhibit good adsorption performance; the maximum adsorption capacity obtained from the Langmuir isotherm-model is 322.58 mg/g, and the adsorption equilibrium was reached in 120 min at a concentration of 300 mg/L. The adsorption kinetics is well described by pseudo-second-order kinetics, and the adsorption equilibrium data are well fitted to the Langmuir isotherm model (R2 = 0.988). Thermodynamics experiments indicate that the adsorption process is both spontaneous and endothermic. In addition, the adsorbent is reusable. We conclude that MOF-5–CMC is a good adsorbent that can be used to remove Pb(II) from aqueous solutions.


2012 ◽  
Vol 9 (4) ◽  
pp. 1823-1834 ◽  
Author(s):  
P. N. Palanisamy ◽  
A. Agalya ◽  
P. Sivakumar

Poly Pyrrle saw dust composite was prepared by reinforcement of natural wood saw dust (obtained fromEuphorbia Tirucalli Lwood) and Poly Pyrrole matrix phase. The present study investigates the adsorption behaviour of Poly Pyrrole Saw dust Composite towards reactive dye. The batch adsorption studies were carried out by varying solution pH, initial dye concentration, contact time and temperature. The kinetic study showed that adsorption of Reactive Red by PPC was best represented by pseudo-second order kinetics with ion exchange adsorption. The equilibrium data were analyzed by Freundlich and Langmuir isotherm model. The equilibrium isotherm data were fitted well with Langmuir isotherm model. The maximum monolayer adsorption capacities calculated by Langmuir model were 204.08 mg/g for Reactive Red at 303 K. The thermodynamic parameters suggest the spontaneous, endothermic nature of ion exchange adsorption with weak Vader walls force of attraction. Activation energy for the adsorption of Reactive by Poly Pyrrole Composite was 11.6387 kJ/mole, Isosteric Heat of adsorption was 48.5454 kJ/mole also supported the ion exchange adsorption process in which forces of attraction between dye molecules and PPC is weak.


2021 ◽  
Author(s):  
Nur Shazwani Abdul Mubarak ◽  
N.N. Bahrudin ◽  
Ali H. Jawad ◽  
B.H. Hameed ◽  
Sumiyyah Sabar

Abstract In this work, sulfonated chitosan montmorillonite composite (S-CS-MT) beads were synthesized using a microwave irradiation method designed to have a better saving-time procedure. The potency of S-CS-MT as an adsorbent was assessed for the removal of cationic dyes such as methylene blue (MB) from aqueous solution. The batch adsorption experiments indicated that MB adsorption onto S-CS-MT follows the Pseudo-second-order kinetic and Langmuir isotherm model. The maximum extent obtained from the Langmuir isotherm model for MB adsorption was 188.2 mg g− 1 at 303 K. The thermodynamic study indicated that the adsorption reaction is favorable and spontaneous. These findings indicated that montmorillonite chitosan grafted with the sulfonate group has the ability and efficacy as biohybrid adsorbent for the adsorption of cationic dyes.


2007 ◽  
Vol 124-126 ◽  
pp. 1781-1784 ◽  
Author(s):  
Yongju Jung ◽  
Jei Won Yeon ◽  
Ji Man Kim ◽  
Hyung Ik Lee ◽  
Seok Kim ◽  
...  

In this study, we modified the surface of nanoporous carbons with carboxymethylated polyethyleneimine (CM-PEI) of a high charge density in order to increase the Pt loading on the nanoporous carbons in an aqueous solution. We carried out equilibrium adsorption tests of Pt(IV) on the pure nanoporous carbon and the CM-PEI-coated carbons and evaluated the adsorption isotherm on the CM-PEI-coated carbon using various isotherm models. It was found that the adsorption of Pt(IV) onto the CM-PEI-coated carbons obeys the Langmuir isotherm model.


2020 ◽  
Vol 17 (1) ◽  
pp. 6 ◽  
Author(s):  
Hao Liu ◽  
Xueying Wang ◽  
Chaofan Ding ◽  
Yuxue Dai ◽  
Yuanling Sun ◽  
...  

Environmental contextGlyphosate is a highly effective and widely used organophosphorus pesticide, but its residues can harm the environment and human health. We report a carboxylated carbon nanotubes-graphene oxide aerogel that can efficiently remove glyphosate from water. This technology has great application prospects in dealing with water contaminated with glyphosate. AbstractGlyphosate, an organophosphorus pesticide, has received considerable attention in recent years owing to its carcinogenic potency. The technologies that remove glyphosate in the environment, especially in water, are important. In this work, we prepare a carboxylated carbon nanotubes-graphene oxide aerogel (cCNTs-GA) by the freeze-drying method for the adsorption of glyphosate. The prepared aerogel exhibits an ultra-low density (7.30mgcm−3), good morphology and strong mechanical strength. Meanwhile, a NaOH solution (0.5molL−1) is selected as an eluent and the adsorption parameters for the adsorption of glyphosate are optimised. The properties of the adsorbents after multiple repetitions and the adsorption mechanism of the cCNTs-GA are also studied. The results show that the adsorbent can be recycled more than 20 times and maintains a good adsorption performance. The maximum adsorption capacity of glyphosate at pH 3 is calculated from the Langmuir isotherm model (546mgg−1 at the temperature of 298K), and the cCNTs-GA exhibits a high adsorption affinity and adsorption capacity for glyphosate, as determined by the partition coefficient (PC). The pseudo-second-order kinetic model fits well to the dynamic behaviour. The equilibrium adsorption process follows the Langmuir isotherm model and the adsorption process is mainly controlled by the intraparticle diffusion model. Furthermore, thermodynamic analysis indicates that the adsorption of glyphosate on the cCNTs-GA is exothermic and spontaneous. The adsorbent is used to remove glyphosate from waste water and the adsorption capacity of the cCNTs-GA for glyphosate is higher than other adsorbents, which indicates that the developed adsorbent has a great potential application in environmental pollution treatment.


2015 ◽  
Vol 21 (1-1) ◽  
pp. 23-33 ◽  
Author(s):  
Odivan Zanella ◽  
Isabel Tessaro ◽  
Liliana Féris

In this study, nitrate (NO3-) removal from aqueous solutions was investigated using granular activated carbon (GAC) modified with CaCl2. Batch sorption studies were performed as a function of sorbent dose, initial nitrate concentration and pH. Sorption was maximized between pH 3 and 9. Studies on the effect of pH showed that the ion exchange mechanism might be involved in the sorption process. The percentage of nitrate removed increased with increasing sorbent concentration, and the ideal sorbent dose was found to be 20 g?L-1. Four isotherm models-Langmuir, Freundlich, Redlich-Peterson and Sips-were used to fit the experimental data. The Redlich-Peterson isotherm model explained the sorption process well and showed the best coefficient of determination (0.9979) and Chi-square test statistic (0.0079). Using the Sips isotherm model, the sorption capacity (qe) was found to be 1.93 mg nitrate per g of sorbent. Kinetic experiments indicated that sorption was a fast process, reaching equilibrium within 120 min. The nitrate sorption kinetic data were successfully fitted to a pseudo-second-order kinetic model. The overall results demonstrated potential applications of modified GAC for nitrate removal from aqueous solutions.


2012 ◽  
Author(s):  
Bassim H. Hameed ◽  
Abdul Rahman Mohamed ◽  
Hui Ying Chong

Kertas kerja ini membincangkan tentang kecekapan penjerap yang lebih murah, iaitu tayar getah terbuang (DRT), dalam menyingkirkan toluena daripada fasa akuas. Penjerapan toluena pada tayar getah terbuang dikaji menggunakan sistem berkelompok pada suhu 25°C dan 30°C. Daripada kajian ini, didapati toluena dapat disingkirkan sehingga 70% dengan menggunakan julat kepekatan awalan antara 50 mg/l hingga 300 mg/l. Dengan menggunakan model keseimbangan terlelurus, iaitu model Langmuir dan Freundlich, keupayaan penjerapan maksimum dapat ditentukan. Daripada data eksperimen, terbukti bahawa walaupun kedua–dua model isoterma Langmuir dan Freundlich boleh menjelaskan data isoterma, tetapi penjerapan toluena pada DRT dapat ditunjukkan dengan lebih baik oleh isoterma Freudlich. Bagi nilai K Freundlich, keupayaan penjerapan ialah 6.6374 mg/l dan 7.7535 mg/l, pada suhu 25°C dan 30°C. Nilai eksponen n Freudlich adalah lebih daripada satu untuk kedua–dua suhu. Kata kunci: Toluena, penjerapan, isoterma, tayar getah terbuang, model isoterma Langmuir, model isoterma Freundlich This paper discusses the effectiveness of a less expensive adsorbent, a discarded rubber tyre (DRT) in removing toluene from aqueuos phase. Adsorption of toluene on a DRT has been studied by using batch system at 25 and 30°C. It was found that up to 70% of toluene was removed for the range of toluene initial concentrations studied between 50–300 mg/l. Using linearized forms of equilibrium models, namely Langmuir and Freundlich models, the maximum adsorptive capacities were determined. It was evident from the experimental data that, although both Langmuir and Freundlich isotherm models could describe the isotherm data, the adsorption of toluene on a DRT was described well by the Freundlich isotherm. For Freundlich K values, sorption capacities were 6.6374 and 7.7535 mg/l at 25 and 30°C, respectively. The values of Freundlich exponent n were greater than one for both temperatures. Key words: Toluene, adsoprtion, isotherms, discarded rubber tyre, Langmuir isotherm model, Freundlich isotherm model


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