scholarly journals Thermodynamics, kinetics, and isotherms for phenol removal from wastewater using red mud

2020 ◽  
Vol 15 (3) ◽  
pp. 705-722 ◽  
Author(s):  
Ashanendu Mandal ◽  
Basab Brata Dey ◽  
Sudip Kumar Das
Keyword(s):  
Kinetic Model ◽  
Red Mud ◽  
Scale Up ◽  
Optimum Operating ◽  
Phenol Removal ◽  
Order Kinetic ◽  
Optimum Operating Condition ◽  
Adsorption Mechanisms ◽  
Order Kinetic Model ◽  
Kinetics And Isotherms

Abstract The phenol removal through adsorption using industrial waste has been studied. The red mud generated as waste in the aluminum plants was used in this research. The surface characterizations of red mud were assessed. The batch experiment was investigated with pH (2–12), adsorption period (120–600 min), phenol content (40–200 mg/L), adsorbent dose (2–7 g/L), and temperature (30–50 °C). At the optimum operating condition, the percentage of phenol removal was 87.5%. The pseudo-second-order kinetic model (r2 = 0.98625–0.99994) fitted better than the pseudo-first-order kinetic model. The Freundlich isotherm model was best fitted (r2 = 0.99734–0.99955) among Langmuir, Dubinin–Radushkevich (D-R), and Temkin isotherms. The Langmuir monolayer adsorption capacity was 49.30966 mg/g at 30 °C. The adsorption mechanisms were supported by Reichenberg, Fick, Elovich, Furusawa, and Smith and Boyd models (r2 > 0.8). The thermodynamics suggested endothermic, random, and spontaneous adsorption above 50 °C. The scale-up design using the Langmuir isotherm, and the disposal of used adsorbent after incineration, was established in this study. The research concludes that the red mud generated from the aluminum plant can be used to remove the phenol from wastewater.

scholarly journals Sea Almond as a Promising Feedstock for Green Diesel: Statistical Optimization and Power Rate Law Based Chemical Kinetics of Its Consecutive Irreversible Methanolysis

Prunus ◽  
2020 ◽  
Author(s):  
Chizoo Esonye ◽  
Okechukwu Donminic Onukwuli ◽  
Akuzuo Uwaoma Ofoefule ◽  
Cyril Sunday Ume ◽  
Nkiruka Jacintha Ogbodo
Keyword(s):  
Kinetic Model ◽  
Chemical Kinetics ◽  
Seed Oil ◽  
Scale Up ◽  
Statistical Optimization ◽  
Industrial Scale ◽  
Order Kinetic ◽  
Rate Law ◽  
Power Rate ◽  
Order Kinetic Model

For successful industrial scale-up and effective cost analysis of transesterification process, presentation of complimentary research data from process optimization using statistical design techniques, chemical kinetics and thermodynamics are essential. Full factorial central composite design (FFCCD) was applied for the statistical optimization of base methanolysis of sea almond (Terminalia catappa) seed oil using response surface methodology (RSM) coupled with desirability function analysis on quadratic model. Reaction time had the most significant impact on the biodiesel yield. Optimum conditions for biodiesel yield of 93.09 wt% validated at 92.58 wt% were 50.03°C, 2.04 wt% catalyst concentration, 58.5 min and 4.66 methanol/oil molar ratio with overall desirability of 1.00. Ascertained fuel properties of the FAME were in compliance with international limits. GC–MS, FTIR and NMR characterizations confirmed unsaturation and good cold-flow qualities of the biodiesel. Based on power rate law, second-order kinetic model out-performed first-order kinetic model. Rate constants of the triglyceride (TG), diglycerides (DG) and monoglycerides (MG) hydrolysis were in the range of 0.00838–0.0409 wt%/min while activation energies were 12.76, 15.83 and 22.43 kcal/mol respectively. TG hydrolysis to DG was the rate determining step. The optimal conditions have minimal error and would serve as a springboard for industrial scale-up of biodiesel production from T. catappa seed oil.

Comparison of the fixation of several metal ions onto a low-cost biopolymer

2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Low Cost ◽  
Operating Conditions ◽  
Order Kinetic ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Beet Pulp ◽  
Removal Of Metal Ions

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.

scholarly journals Investigation of Seeds and Peels of Citrullus colocynthis as Efficient Natural Adsorbent for Methylene Blue Dye

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1279
Author(s):  
Wafa Mohammed Alghamdi ◽  
Ines El Mannoubi
Keyword(s):  
Methylene Blue ◽  
Kinetic Model ◽  
Langmuir Isotherm ◽  
Order Kinetic ◽  
Citrullus Colocynthis ◽  
Natural Adsorbent ◽  
Spontaneous Process ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Mb Adsorption

Natural adsorbents as low-cost materials have been proved efficient for water remediation and have significant capacity for the removal of certain chemicals from wastewater. The present investigation aimed to use Citrullus colocynthis seeds (CCSs) and peels (CCPs) as an efficient natural adsorbent for methylene blue (MB) dye in an aqueous solution. The examined biosorbents were characterized using surface area analyzer (BET), scanning electron microscope (SEM), thermogravimetric analyzer (TGA) and Fourier transform infra-red (FT-IR) spectroscopy. Batch adsorption experiments were conducted to optimize the main factors influencing the biosorption process. The equilibrium data for the adsorption of MB by CCSs were best described by the Langmuir isotherm followed by the Freundlich adsorption isotherms, while the equilibrium data for MB adsorption by CCPs were well fitted by the Langmuir isotherm followed by the Temkin isotherm. Under optimum conditions, the maximum biosorption capacity and removal efficiency were 18.832 mg g−1 and 98.00% for MB-CCSs and 4.480 mg g−1 and 91.43% for MB-CCPs. Kinetic studies revealed that MB adsorption onto CCSs obeys pseudo-first order kinetic model (K1 = 0.0274 min−1), while MB adsorption onto CCPs follows the pseudo-second order kinetic model (K2 = 0.0177 g mg−1 min−1). Thermodynamic studies revealed that the MB biosorption by CCSs was endothermic and a spontaneous process in nature associated with a rise in randomness, but the MB adsorption by CCPs was exothermic and a spontaneous process only at room temperature with a decline in disorder. Based on the obtained results, CCSs and CCPSs can be utilized as efficient, natural biosorbents, and CCSs is promising since it showed the highest removal percentage and adsorption capacity of MB dye.

Dyeing mechanism and photodegradation kinetics of gardenia yellow natural colorant

2020 ◽  
pp. 004051752095848
Author(s):  
Huiyu Jiang ◽  
Xiaodong Hu ◽  
Asfandyar Khan ◽  
Jinbo Yao ◽  
Muhammad Tahir Hussain
Keyword(s):  
Kinetic Model ◽  
Cotton Fabric ◽  
Reaction Rate Constant ◽  
Second Order ◽  
Order Kinetic ◽  
Natural Colorant ◽  
Yellow Solution ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Dyeing Rate

In this study, gardenia yellow solution is used to dye 100% cotton fabric. The dyeing rate curve and adsorption isotherms were recorded to explore the thermodynamic model and to calculate the corresponding parameters. A definite concentration of gardenia yellow solution was placed under the xenon arc lamp for irradiation to test its photodegradability. Absorbance of the solution was measured at different degradation times and the corresponding varying curve of the absorbance was drawn to explore the photodegradation reaction order of the natural colorant and consistent parameters were calculated. The experimental results proved that the dyeing of cotton fabric with gardenia yellow colorant followed the pseudo second order kinetic model whereas adsorption isotherm followed the Langmuir model and the photodegradation process followed the second order kinetic model. Values of different parameters were calculated: reaction rate constant k = 2.26 × 10–3 (mg · L−1)1−m h−1, the correlation coefficient R2 = 0.994, and half decay time t1/2 = 5.82 h.

Iron Chelation by Polyamidoamine Dendrimers: A Second-Order Kinetic Model for Metal–Amine Complexation

2011 ◽  
Vol 115 (46) ◽  
pp. 13534-13540 ◽  
Author(s):  
Michael R. Mankbadi ◽  
Mohamed A. Barakat ◽  
Mohamed H. Ramadan ◽  
H. Lee Woodcock ◽  
John N. Kuhn
Keyword(s):  
Kinetic Model ◽  
Iron Chelation ◽  
Second Order ◽  
Order Kinetic ◽  
Polyamidoamine Dendrimers ◽  
Order Kinetic Model ◽  
Metal Amine

scholarly journals Preparation of Activated Biochar-Supported Magnetite Composite for Adsorption of Polychlorinated Phenols from Aqueous Solutions

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1899 ◽  
Author(s):  
Jun ◽  
Kim ◽  
Han ◽  
Yoon ◽  
Kim ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Hydrophobic Interactions ◽  
Order Kinetic ◽  
Adsorption Selectivity ◽  
Adsorption Mechanisms ◽  
Activated Biochar ◽  
Experimental Parameters ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Cetrimonium Bromide

For this study, we applied activated biochar (AB) and its composition with magnetite (AB-Fe3O4) as adsorbents for the removal of polychlorophenols in model wastewater. We comprehensively characterized these adsorbents and performed adsorption tests under several experimental parameters. Using FTIR, we confirmed successful synthesis of AB-Fe3O4 composite through cetrimonium bromide surfactant. We conducted adsorption tests using AB and AB-Fe3O4 to treat model wastewater containing polychlorophenols, such as 2,3,4,6-Tetrachlorophenol (TeCP), 2,4,6-Trichlorophenol (TCP), and 2,4-Dichlorophenol (DCP). Results of the isotherm and the kinetic experiments were well adapted to Freundlich’s isotherm model and the pseudo-second-order kinetic model, respectively. Main adsorption mechanisms in this study were attributed to non-covalent, π-electron acceptor–donor interactions and hydrophobic interactions judging from the number of chloride elements in each chlorophenol and its hydrophobic characteristics. We also considered the electrostatic repulsion effect between TeCP and AB, because adsorption performance of TeCP at basic condition was slightly worse than at weak acidic condition. Lastly, AB-Fe3O4 showed high adsorption selectivity of TeCP compared to other persistent organic pollutants (i.e., bisphenol A and sulfamethoxazole) due to hydrophobic interactions. We concluded that AB-Fe3O4 may be used as novel adsorbent for wastewater treatment including toxic and hydrophobic organic pollutants (e.g., TeCP).

scholarly journals Adsorption removal of Cr(VI) by isomeric FeOOH

2019 ◽  
Vol 80 (2) ◽  
pp. 300-307
Author(s):  
Di Zhang ◽  
Jiaxin Liu ◽  
Shibei Zhu ◽  
Huixin Xiong ◽  
Yiqun Xu
Keyword(s):  
Active Sites ◽  
Correlation Coefficients ◽  
Order Kinetic ◽  
Isothermal Adsorption ◽  
Adsorption Mechanisms ◽  
Ph Values ◽  
Adsorption Removal ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Theoretical Evidence

Abstract The aim of this work is to study the performances of isomeric α-, β-, and γ-FeOOH (goethite, akaganéite and lepidocrocite, including five samples named as Gth1 and Gth2, Aka1 and Aka2, and Lep, respectively) for removing hexavalent chromium (Cr(VI)) from aqueous solutions. The adsorption mechanisms were explored by kinetic and isothermal experiments. Adsorption efficiencies under the different pH values, anions, and the levels of adsorbate and adsorbent were also measured. Results showed that the Cr(VI) adsorption by isomeric FeOOH could be best described by pseudo-second-order kinetic model. The processes of Cr(VI) isothermal adsorption could be greatly fitted by the Langmuir and Freundlich equations with the high correlation coefficients of R2 (>0.92). Also, there were the optimum pH values of 3.0–8.0 for FeOOH to adsorb Cr(VI), and their adsorption capacities were tightly related with the active sites of adsorbents. Cr(VI) adsorptions by these adsorbents were easily influenced by H2PO4–, and then SO42–, while there were little effects by Cl–, CO32– and NO3–. These obtained results could provide a potentially theoretical evidence for isomeric FeOOH materials applied in the engineering treatment of the polluted chromate-rich waters.

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