scholarly journals Isotherms, Kinetics and Break through Curve for Sorptive Removal of Chromium from Wastewater by Activated Sludge

2019 ◽  
Vol 31 (8) ◽  
pp. 1704-1708
Author(s):  
Sunil Kulkarni
Keyword(s):  
Activated Sludge ◽  
Freundlich Isotherm ◽  
Break Point ◽  
Sorption Process ◽  
Low Flow ◽  
Maximum Adsorption Capacity ◽  
Physical And Chemical ◽  
Chromium Uptake ◽  
Better Than ◽  
Sorptive Removal

In the present investigations, activated sludge is used for removal of chromium in batch and continuous mode. It was observed that the sorption process followed Langmuir isotherm better than Freundlich isotherm (R2 = 0.95). The Freudlich model with R2 value above 0.9 suggests that the sorptive removal may involve physical and chemical adsorption with some multilayer sorption. Chromium uptake followed second order kinetics. The maximum adsorption capacity qe was observed to be 208.33 mg/g. The breakeven time and exhaustion time were determined for continuous operation. The non-availability of adsorbate at low flow rates play important role in delaying the break point time. Sludge age and initial concentration also affect the removal of chromium. The data follows the Thomas model with R2 value more than 0.9.

scholarly journals Adsorption of chlortetracycline onto biochar derived from corn cob and sugarcane bagasse

2018 ◽  
Vol 78 (6) ◽  
pp. 1336-1347 ◽  
Author(s):  
Lin Zhang ◽  
Lei Tong ◽  
Pengguang Zhu ◽  
Peng Huang ◽  
Zhengyu Tan ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Sugarcane Bagasse ◽  
Adsorption Kinetics ◽  
Freundlich Isotherm ◽  
Maximum Adsorption Capacity ◽  
Corn Cob ◽  
Alternative Materials ◽  
Pseudo Second Order ◽  
Kinetics And Isotherms ◽  
Better Than

Abstract Biochar was prepared from two different types of biological waste materials, corn cob (CC) and sugarcane bagasse (SB). The adsorption capacity of each class of adsorbent was determined by chlortetracycline (CTC) adsorption tests. The adsorption kinetics and isotherms of chlortetracycline onto sugarcane bagasse biochar (SBB) and corn cob biochar (CCB) were studied. Experimental results indicated that pseudo-second-order adsorption kinetics of CTC onto SBB and CCB were more reasonable than pseudo-first-order kinetics, and the adsorption kinetic model of CTC onto SBB was slightly better than that onto CCB. The maximum adsorption capacity of CTC onto SBB was 16.96 mg/g at pH 4, while the highest adsorption efficiency of CTC onto CCB was achieved at pH 5 with a maximum adsorption of 12.39 mg/g. The Freundlich isotherm model was better than the Langmuir model at illustrating the adsorption process of CTC onto SBB and CCB. These results provide a way to understand the value of specific biochars, which can be used as efficient and effective adsorbents for CTC removal from waste-water. Compared with raw pinewood, SBB and CBB were considered as alternative materials to remove antibiotics from aqueous environments.

Nucleophilicity and its parametrization

1989 ◽  
Vol 54 (1) ◽  
pp. 117-135
Author(s):  
Oldřich Pytela ◽  
Vítězslav Zima
Keyword(s):  
Regression Analysis ◽  
Linear Correlation ◽  
Correlation Equation ◽  
Chemical Processes ◽  
General Tendency ◽  
Orbital Interaction ◽  
Physico Chemical ◽  
Physical And Chemical ◽  
Two Parameter ◽  
Better Than

The method of conjugate deviations based on the regression analysis has been suggested for construction of a new nucleophilicity scale. This method has been applied to a set of 28 nucleophiles participating in 47 physical and chemical processes described in literature. The two-parameter nucleophilicity scale obtained represents-in the parameter denoted as ND-the general tendency to form a bond to an electrophile predominantly on the basis of the orbital interaction and-in the parameter denoted as PD-the ability to interact with a centre similar to the proton (basicity). The linear correlation equation involving the ND, PD parameters and the charge appears to be distinctly better than the most significant relations used. The correlation dependences have the physico-chemical meaning. From the position of individual nucleophiles in the space of the ND and PD parameters, some general conclusions have been derived about the factors governing the reactivity of nucleophiles.

scholarly journals Improved chromatic and sensory characteristics of Plavac Mali wines – efficiency of maceration enzymes

2017 ◽  
Vol 35 (No. 3) ◽  
pp. 236-245 ◽  
Author(s):  
IVANA ALPEZA ◽  
KARIN KOVAČEVIĆ GANIĆ ◽  
ANDREJA VANZO ◽  
STANKA HERJAVEC
Keyword(s):  
Sensory Quality ◽  
Yeast Cells ◽  
Enzyme Preparations ◽  
Pectolytic Enzymes ◽  
Colour Parameters ◽  
The Moment ◽  
Red Grape ◽  
Different Characteristics ◽  
Physical And Chemical ◽  
Better Than

Two commercial enzyme preparations were used in the production of wine from the Croatian autochthonous red grape variety Plavac Mali in order to improve the extraction of polyphenolic components from grapes, chromatic parameters, and sensory quality. During two vintages, the conventional maceration without enzymes was compared with the maceration using products with different characteristics: pectinase with additional cellulase and hemicellulase activity and pectinase with inactive yeast cells. Both products affected polyphenolic extraction and colour parameters: intensity and hue, and ratio between the yellow, red, and blue colour in young wines (2 months after fermentation) and at the moment of bottling (9 months after fermentation). The correlation between anthocyanins and colour intensity was very strong. The expected reduction of quantitative chromatic parameters during aging was confirmed. Significantly better results were observed in wines produced with pectinase, in relation to all analysed physical and chemical parameters. The sensory analysis showed that wines produced with pure pectolytic enzymes were significantly better than those produced without the enzymes. A product of the combination of pectolytic enzymes and inactive yeast cells had a partial influence on the improvement of the phenolic and sensory quality. The overall quality was significantly more expressed in wines produced with pectolytic enzymes, especially in young wines.

Biosorption of Cadmium onto Pseudomonas fluorescens: Application of Isotherm and Kinetic Models

2010 ◽  
Vol 171-172 ◽  
pp. 49-52 ◽  
Author(s):  
Chang Li Yu ◽  
Zhi Peng Lu ◽  
Fa Zhi Ge ◽  
Er Li Zhao
Keyword(s):  
Pseudomonas Fluorescens ◽  
Functional Groups ◽  
Metal Ion ◽  
Freundlich Isotherm ◽  
Industrial Effluents ◽  
Rate Equations ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Kinetics Of Adsorption ◽  
Isotherm And Kinetic Models

The present study was undertaken to evaluate the feasibility of Pseudomonas fluorescens biomass for the removal of cadmium ions from aqueous solutions. Batch experiments were performed to study the adsorption of cadmium on pH, Pseudomonas fluorescens biomass adsorbent with respect to initial Cd(II) concentration, contact time and biomass dose. The experimental data were modeled by Langmuir and Freundlich isotherm models. Langmuir model resulted in the best fit of the adsorption data. The maximum adsorption capacity for Cd(II) was 66.25 mg/g (pH 5.0 and 5 g/L biomass dose). Kinetics of adsorption followed second-order rate equations. The FTIR results of Pseudomonas fluorescens biomass showed that biomass has different functional groups and these functional groups are able to react with metal ion in aqueous solution. The results of the present study suggest that Pseudomonas fluorescens biomass can be used beneficially in treating industrial effluents containing heavy metal ions.

scholarly journals Phenol adsorption from wastewater using cashew nut shells as adsorbent

2018 ◽  
Vol 7 (3) ◽  
pp. 966
Author(s):  
Kartik Kulkarni ◽  
Varsha Sudheer ◽  
C R Girish
Keyword(s):  
Agricultural Waste ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Multilayer Adsorption ◽  
Phenol Adsorption ◽  
Cashew Nut ◽  
Experimental Parameters ◽  
Order Kinetic Model

The potential of agricultural waste cashew nut shells as an adsorbent for removing phenol from wastewater is presented in this paper. The adsorbent was treated with 3M sulphuric acid in order to improve the properties. The experimental parameters such as adsorbent dosage, concentration and temperature were optimized with response surface methodology (RSM). The isotherm data were tested with different isotherm models and it obeyed Freundlich Isotherm showing the multilayer adsorption. The kinetic data satisfied pseudo-first order kinetic model. The maximum adsorption capacity was calculated to be 35.08 mg/g proving the capability of cashew nut shells for removing phenol from wastewater.  

A COMPARISON OF VARIOUS MEANS OF MEASURING THE DEGREE OF DECOMPOSITION OF VIRGIN PEAT MATERIALS IN THE CONTEXT OF THEIR RELATIVE BIODEGRADABILITY

1979 ◽  
Vol 59 (4) ◽  
pp. 397-400 ◽  
Author(s):  
M. P. LÉVESQUE ◽  
S. P. MATHUR
Keyword(s):  
Chemical Properties ◽  
Fiber Content ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
Better Than ◽  
And Chemical Properties

Eleven physical and chemical properties of 26 peat materials from a total of five virgin profiles were determined and statistically analyzed for correlations among attributes that relate to the degree of decomposition, and with the rates at which the materials biodegraded. Estimation of fiber content made routinely by pedologists in the field correlated with relative, biodegradability better than any other criterion of decomposition and humification.

Biosorption of Eosin by Chemically Modified Peanut Husk

2011 ◽  
Vol 233-235 ◽  
pp. 439-443
Author(s):  
Ying Hua Song ◽  
Sheng Ming Chen
Keyword(s):  
Freundlich Isotherm ◽  
Sorption Process ◽  
Intraparticle Diffusion ◽  
Transfer Model ◽  
Experimental Conditions ◽  
Isotherm Equation ◽  
Chemically Modified ◽  
Pseudo Second Order ◽  
Uptake Studies ◽  
Rate Controlling Step

The sorption of eosin by peanut husk, which was chemically modified by formaldehyde in acidic medium was studied with variation in the parameters of contact time, pH, initial eosin concentration and temperature. They were used for equilibrium sorption uptake studies with eosin. The results indicate that sorption equilibrium could be well described by the Freundlich isotherm equation. The sorption followed the pseudo-second order model. The mass transfer model as intraparticle diffusion was applied to the experimental data to examine the mechanisms of the rate controlling step. It was found that the intraparticle diffusion is becoming the significant controlling step under the experimental conditions. The thermodynamic constants of the sorption process were also evaluated, which suggest an endothermic physical sorption process which runs spontaneously.

TRUE AND APPARENT METABOLIZABLE ENERGY VALUES FOR POULTRY OF CANADIAN WHEATS AND OATS MEASURED BY BIOASSAY AND PREDICTED FROM PHYSICAL AND CHEMICAL DATA

1977 ◽  
Vol 57 (2) ◽  
pp. 365-374 ◽  
Author(s):  
I. R. SIBBALD ◽  
K. PRICE
Keyword(s):  
Metabolizable Energy ◽  
Chemical Data ◽  
Accuracy And Precision ◽  
Apparent Metabolizable Energy ◽  
The Difference ◽  
Variation Explained ◽  
Predicted Values ◽  
Naked Oats ◽  
Physical And Chemical ◽  
Better Than

Thirty samples of wheat and 28 samples of oats were assayed for true and apparent metabolizable energy (TME, AME). Within grains, the difference TME−AME increased with decreasing AME values; there is evidence that this trend is associated with reduced voluntary consumption of AME assay diets containing low energy grains. The TME and AME data were compared with ME values predicted from physical and chemical data describing the grains. Previously published prediction equations were tested and new equations were derived. Comparisons between predicted and observed data suggested that both the TME and AME values of wheat were predicted with insufficient accuracy and precision for practical use. Similar comparisons using the oat data showed high correlations between observed and predicted values, although the predictions were no more accurate than for wheat; however, when data describing four samples of naked oats were removed, the correlations were reduced substantially. Comparisons involving data for the hulled oats indicated that most equations were able to predict AME better than TME. Multiple regression analysis was used to identify those combinations of variables best able to predict TME data. No combination of variables was best for both wheat and oats. The combinations of variables used in published equations performed quite well. With four variables, the percentage of the TME variation explained was as high as 52 for wheat, 82 for oats and 64 for hulled oats. Predictions based on air-dry data are associated with higher correlations than those based on dry matter data, but the air-dry predictions are the less useful in practice. The reason for this is discussed.

Kinetics of lead ion biosorption from aqueous solution onto lyophilized Aspergillus niveus

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Hülya Karaca ◽  
Turgay Tay ◽  
Merih Kıvanç
Keyword(s):  
Adsorption Capacity ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Lead Ions ◽  
Lead Ion ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Aspergillus Niveus ◽  
Pseudo Second Order

The biosorption of lead ions (Pb2+) onto lyophilized fungus Aspergillus niveus was investigated in aqueous solutions in a batch system with respect to pH, contact time and initial concentration of the ions at 30 °C. The maximum adsorption capacity of lyophilized A. niveus was found to be 92.6 mg g−1 at pH 5.1 and the biosorption equilibrium was established about in 30 min. The adsorption capacity obtained is one of the highest value among those reported in the literature. The kinetic data were analyzed using the pseudo-first-order kinetic, pseudo-second-order kinetic, and intraparticle diffusion equations. Kinetic parameters, such as rate constants, equilibrium adsorption capacities, and related correlation coefficients for the kinetic models were calculated and discussed. It was found that the adsorption of lead ions onto lyophilized A. niveus biomass fit the pseudo-second-order kinetic model well. The Langmuir and Freundlich isotherm parameters for the lead ion adsorption were applied and the Langmuir model agreed better with the adsorption of lead ions onto lyophilized A. niveus.

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