scholarly journals Non-linear Regression Analysis for the Adsorption Kinetics and Equilibrium Isotherm of Phenacetin onto Activated Carbons

2019 ◽  
pp. 1-18 ◽  
Author(s):  
Christian Sadeu Ngakou ◽  
Gabche Solomon Anagho ◽  
Horace Manga Ngomo
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Activated Carbons ◽  
Linear Regression Analysis ◽  
Xrd Analysis ◽  
Strong Interactions ◽  
Isotherm Models ◽  
Linear Isotherm ◽  
Non Linear ◽  
Best Fit

Activated carbon obtained from ayous sawdust, Cucurbitaceae (egussi) peelings and the mixture of the two were studied for the adsorption of phenacetin. Characterisation of activated carbon by SEM and XRD analysis shows that the mixture of precursors combine the properties of activated carbon obtained separately. The well-knownbatch sorption models– Langmuir (one and two sites), Freudlich, Tempkin, Elovich, Langmuir-Freudlich, Redlich Peterson, Radke-Prausnitz, Fritz Shlunder)—were tested with experimental data for the adsorption of phenacetin to estimate adsorption equilibrium parameters—rate constantsand adsorption capacities. The model with the best fit was identified from extensive statistical analysis of the results of nonlinear regression of the experimental data. Comparison of the statistical errors in parameter estimation between linear and non-linear isotherm models shows that transformation of non-linear isotherm equations to linear forms implicitly alter their error structure. The much smaller size of the various error indicators —Determination Coefficient, R2; Sum of Square Errors, SSE; Chi Test, χ2; Average Relative Errors, ARE—, calculated for the case of non linearization when compared to linearization, indicate the greater accuracy in the application of non linearization. The Langmuir model (one site) gave the best fit and thus the values of adsorption capacity for each activated carbon were calculated from it. Kinetic models show that weak and strong interactions are involved in the adsorption process and that the controlling mechanism may not be limited to intra particle diffusion. The lower value of the boundary layer thickness in the case of activated carbon obtained from the mixture, justified the higher adsorbed quantity of this activated carbon compared to those of activated carbon from each precursor.

Removal of basic dyes from aqueous solutions by activated carbon derived from Eichornia crassipes: equilibrium and kinetic studies

2014 ◽  
Vol 49 (2) ◽  
pp. 163-178 ◽  
Author(s):  
Syed Usman Nasrin Banu ◽  
G. Maheswaran
Keyword(s):  
Activated Carbon ◽  
Linear Regression ◽  
Second Order ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Non Linear ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Eichornia Crassipes ◽  
Best Fit

The feasibility of preparing activated carbon from Eichornia crassipes by chemical activation was investigated. Batch experiments were carried out for the sorption of Methylene Blue (MB) and Rhodamine B (RB) onto the prepared activated carbon. The variables studied were initial dye concentration, pH, adsorbent dose, and contact time. Equilibrium data for the adsorption of the dyes onto activated carbon were obtained from batch adsorption experiments. Two-parameter isotherm models including Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich were employed for fitting equilibrium data. Three-parameter isotherm models including Redlich–Peterson, Toth, and Koble–Corrigan models were also employed for fitting the equilibrium data. Linear and non-linear regression methods were used to determine the best fit model to the equilibrium data. It was found that non-linear regression is a better method for determining isotherm parameters. The data were fitted to pseudo-first-order, pseudo-second-order, intraparticle diffusion model, and Elovich equation. The pseudo-second-order model gave the best fit to the equilibrium data as seen from correlation coefficient values. Fourier transform infrared spectroscopy and scanning electron microscopic investigations were carried out to confirm the morphological characteristics of the adsorbent. The prepared activated carbon had greater affinity for adsorbing MB when compared to RB.

scholarly journals CURVAS DE SECAGEM E AVALIAÇÃO DA ATIVIDADE DE ÁGUA DA BANANA PASSA

2004 ◽  
Vol 22 (1) ◽  
Author(s):  
MILTON CANO-CHAUCA ◽  
AFONSO M. RAMOS ◽  
PAULO C. STRINGHETA ◽  
JOSÉ ANTONIO MARQUES ◽  
POLLYANNA IBRAHIM SILVA
Keyword(s):  
Experimental Data ◽  
Linear Regression ◽  
Moisture Content ◽  
Water Activity ◽  
Linear Regression Analysis ◽  
Sorption Isotherms ◽  
Exponential Model ◽  
Drying Time ◽  
Non Linear ◽  
Drying Curves

Curvas de secagem de banana passa foram determinadas, utilizando-se três temperaturas do ar de secagem. Os resultados indicaram que para reduzir o teor de umidade do produto até 23,5% foram necessários tempos de secagem de 51, 36 e 30 horas paras as temperaturas de 50, 60 e 70ºC, respectivamente. O modelo exponencial U/Uo = exp(-kt) foi ajustado para os dados experimentais mediante análise de regressão não-linear, encontrandose alto coeficiente de regressão linear. Determinou-se a atividade de água do produto ao longo do processo de secagem para as três temperaturas testadas. Estudou-se a correlação entre a atividade de água e o teor de umidade do produto, determinando-se as isotermas de dessorção da banana passa a 25ºC. Observou-se que a atividade de água diminuiu em função do tempo de secagem e do teor de umidade para as três temperaturas de secagem. Os dados experimentais foram ajustados mediante regressão não-linear ao modelo polinomial e a seguinte equação foi obtida: U = -1844,93 + 7293,53Aa – 9515,52Aa2 + 4157,196Aa3. O ajuste mostrou-se satisfatório (R2 > 0,90). DRYING CURVES AND WATER ACTIVITY EVALUATION OF THE BANANA-PASSES Abstract Banana drying curves were determined by utilizing three drying air temperatures. The results indicated that to reduce the moisture content of the product until 23.5% it were necessary drying times of 51, 36 and 30 hours for temperatures of 50, 60 and 70ºC, respectively. The exponential model U/Uo = exp(-kt) was adjusted for the experimental data by means of non linear regression analysis, and a high coefficient of linear regression was found. The water activity of the product was determined throughout the drying process for the three tested temperatures. The correlation between the water activity and moisture content of the product was studied, and the sorption isotherms were determined at 25º C. It was observed that the water activity decreased in function to the drying time and moisture content for the three drying temperatures. The experimental data were adjusted by means of non linear regression to the polynomial model and the following equation was obtained: U = - 1844.93 + 7293.53A a – 9515.52 Aa 2 + 4157.196A a 3. The final adjust was satisfactory (R2 > 0.90).

scholarly journals EXPLORATION OF INTERCALATED KAOLINITE CLAY FOR THE UPTAKE OF BASIC DYE BY ADSORPTION − EQUILIBRIUM, KINETICS AND THERMODYNAMIC STUDIES

2021 ◽  
Vol 46 (1) ◽  
Author(s):  
C. E. Chigbundu ◽  
K. O. Adebowale
Keyword(s):  
Experimental Data ◽  
Linear Regression ◽  
Goodness Of Fit ◽  
Linear Regression Analysis ◽  
Dye Adsorption ◽  
Batch Adsorption ◽  
Sem Images ◽  
Kaolinite Clay ◽  
Non Linear ◽  
The Impact

Dyes are complex and sensitive organic chemicals which exposes microbial populations, aquatic lives and other living organisms to its toxic effects if their presence in water bodies or industrial effluents are not properly handled. This work therefore, comparatively studied the adsorption efficiencies of natural raw kaolinite (NRK) clay adsorbent and dimethyl sulphoxide (DMSO) faciley intercalated kaolinite clay (DIK) adsorbent for batch adsorption of Basis Red 2 (BR2) dye. The impact of varying the contact time, temperature and other operating variables on adsorption was also considered. The two adsorbents were characterized using SEM images, FTIR and XRD patterns. Linear and non-linear regression analysis of different isotherm and kinetic models were used to describe the appropriate fits to the experimental data. Error analysis equations were also used to measure the goodness-of-fit. Langmuir isotherm model best described the adsorption as being monolayer on homogenous surfaces while Kinetic studies showed that Elovich model provides the best fit to experimental data. The adsorption capacities of NRK and DIK adsorbents for the uptake of BR2 were 16.30 mg/g and 32.81 mg/g, respectively (linear regression) and 19.30 mg/g and 30.81 mg/g, respectively (non-linear regression). The thermodynamic parameter, ∆G showed that BR2 dye adsorption onto the adsorbents were spontaneous. DIK adsorbent was twice efficient compared with NRK for the uptake of BR2 dye.

scholarly journals Adsorption of propan-1-ol vapour on Sorbonorit 4 activated carbon – equilibrium and dynamic studies

2017 ◽  
Vol 19 (4) ◽  
pp. 59-64 ◽  
Author(s):  
Dorota Downarowicz ◽  
Katarzyna Ziętarska
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Energy Requirement ◽  
Isosteric Heat ◽  
Breakthrough Curves ◽  
Isotherm Models ◽  
Column Studies ◽  
Temperature Isotherm ◽  
Electrothermal Desorption ◽  
Temperature Swing Adsorption

Abstract The study examined the adsorption of propan-1-ol (1PN) vapour on Sorbonorit 4 (S4) activated carbon in cyclic Electrothermal Temperature Swing Adsorption (ETSA) process. Dynamic adsorption capacity and breakthrough time were determined based on column studies. Thomas model was used to describe experimental breakthrough curves. Adsorption isotherms for 1PN vapour on S4 activated carbon were tested at 293 to 413 K. The experimental data were examined by using three multi-temperature isotherm models: Toth, Sips and hybrid Langmuir-Sips. Results indicate that S4 activated carbon is a heterogeneous adsorbent and the hybrid Langmuir-Sips model provides the best-fit experimental data. The energy requirement for 1PN electrothermal desorption from S4 bed (ca. 170–200 kJ/mol) was about 3 to 3.5 times larger than the isosteric heat of adsorption (56.8 kJ/mol), which was calculated using Toth adsorption isotherm.

scholarly journals Adsorption of UV254 in Kerian River water onto ZeliacTM: Analysis using linear and non-linear forms of isotherm models

2017 ◽  
Vol 19 (1) ◽  
pp. 74-81 ◽  
Keyword(s):  
River Water ◽  
Function Analysis ◽  
Low Cost ◽  
Error Function ◽  
Linear Regression Analysis ◽  
Freundlich Isotherm ◽  
Linear Analysis ◽  
Isotherm Models ◽  
Freundlich Isotherms ◽  
Non Linear

<p>The composite media, Zeliac<sup>TM</sup> was developed with the initial aim to provide low cost adsorbent with promising adsorption capacity. This study was conducted to investigate the removal of UV absorbance at 254 nm (UV<sub>254</sub>) in Kerian river water using Zeliac<sup>TM</sup> as the media. Batch experiments study was carried out to determine the optimum removal of UV<sub>254</sub> by Zeliac<sup>TM</sup>. The experimental data were fitted to Langmuir and Freundlich isotherms to investigate the adsorption mechanism. The results from batch study exhibit that Zeliac<sup>TM</sup> is capable to remove 74.4% UV<sub>254</sub> at the dosage of 7g/100 ml. Linear isotherm analysis suggests that the best fitting linear line is Freundlich isotherm with R<sup>2</sup> values of 0.9294 indicating multilayer adsorption. Similarly, non-linear regression analysis reveals that the adsorption of UV<sub>254</sub> by Zeliac<sup>TM</sup> is attributed by physisorption. The non-linear Freundlich isotherm gives a better fit to the adsorption of UV<sub>254</sub> than Langmuir isotherm with R<sup>2</sup> values of 0.9488. The results are supported with low values of X<sup>2</sup>, ARE, HYBRID and MPSED from the error function analysis.&nbsp; Additionally, it is noted that the linear analysis overestimates the constant parameters’ values for Freundlich isotherm, which cause larger errors as estimated by the error function analysis. Hence, non-linear analysis is more appropriate in explaining the batch experiment data.</p>

scholarly journals A Comparative Study of COD Removal Efficacy from Pharmaceutical Wastewater by Areca Nut Husk Produced and Commercially Available Activated Carbons

2021 ◽  
pp. 47-56
Author(s):  
Sharmin Akter ◽  
Ferdousi Sultana ◽  
Md. Rakibul Kabir ◽  
Partha Pratim Brahma ◽  
Atkeeya Tasneem ◽  
...  
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Organic Contaminants ◽  
Activated Carbons ◽  
Low Cost ◽  
Oxygen Demand ◽  
Areca Nut ◽  
Pharmaceutical Wastewater ◽  
Adsorption Processes ◽  
Pharmaceutical Industries

Pharmaceutical industries in Bangladesh are considered as one major industrial as well as environmental pollution problems which discharge a significant amount of organic contaminants in the environment hence require advanced treatment technologies to decontaminate pharmaceutical wastewater. In the present investigation, areca nut husk treated activated carbon (ANHC) was used as an adsorbent to remove chemical oxygen demand (COD) from pharmaceutical effluent as well as a comparative adsorption efficiency with commercial activated carbon (CAC) was performed.  The batch experiments were carried out in a laboratory scale. The materials also evaluated for different adsorbent dosages and contact times. The experiment revealed a removal percentage up to 70% for ANHC and 90% for CAC for 3g of adsorbents in 180 min. The adsorption processes were satisfactorily described by pseudo-second-order (PSO) kinetic model which shows a better fitting with the maximum regression coefficient for both adsorbents. The results show that Langmuir model best described the experimental data with a highest correlation coefficient (R2=0.9856 for ANHC and 0.9993 for CAC) compared to Freundlich model and the experimental data showed asorption capacity of 36.549 and 64.935 mg/g for ANHC and CAC, correspondingly. According to the adsorption studies, the results revealed that COD adsorption process followed by the monolayer chemisorption mechanisms. The results revealed that ANHC adsorbent is potentially low cost and environmental friendly adsorbent for the removal of organic matter from pharmaceutical effluent.

Adsorption of 2,4-dinitrophenol on Activated Carbon Prepared from Cotton Cakes: Non-linear Isotherm Modeling

2018 ◽  
Vol 24 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Bopda Aurelien ◽  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Kamdem Tamo Arnaud ◽  
Anagho Solomon Gabche
Keyword(s):  
Activated Carbon ◽  
Isotherm Modeling ◽  
Linear Isotherm ◽  
Non Linear

scholarly journals Comparison of Surface and Structural Properties of Carbonaceous Materials Prepared by Chemical Activation of Tomato Paste Waste: The Effects of Activator Type and Impregnation Ratio

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Nurgul Ozbay ◽  
Adife Seyda Yargic
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Low Cost ◽  
Chemical Activation ◽  
Nitrogen Adsorption ◽  
Xrd Analysis ◽  
Point Of Zero Charge ◽  
Activation Process ◽  
X Ray ◽  
Tomato Paste

Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C). The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.%) on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW), and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG), Fourier transform-infrared (FT-IR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, point of zero charge measurements (pHPZC), particle size analyzer, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD) analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g) was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.

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