scholarly journals Preparation and characterization of activated carbon from wheat straw to remove2, 4-dichlorophenoxy acetic acid from aqueous solutions

2021 ◽  
pp. 175-186
Author(s):  
Molla Tefera ◽  
Mengistu Tulu

This study was focused to investigate the adsorptive behavior of activated carbon prepared from wheat straw treated with acid and base for the removal of 2, 4-dichlorophenoxy acetic acid (2,4-D). The morphology of the adsorbent was characterized using infrared spectroscopy and scanning electron microscopy. Compared with acid activated wheat straw, base activated wheat straw has provided lower ash content, moisture and volatile matter. However, it has higher iodine number than acid activated wheat straw. The removal of 2,4-D from aqueous solution was investigated at various physicochemical parameters such as pH (2–10), contact time (5–60 min), temperature (20-80 oC), amount of adsorbent (0.1-1.4 g) and initial concentration of 2,4-D (1.0-25 mg/L). The removal efficiency of 2,4-D in aqueous solution was found to be 92.02%. The equilibrium data were analyzed using Langmuir and Freundlich isotherm and the Langmuir model better describes that the active adsorption sites were homogeneously distributed on the surface of the adsorbent. Therefore, the activated carbon prepared from wheat straw treated with base can be used as efficient and cost-effective method to remove 2,4-D from aqueous solution.

2015 ◽  
Vol 754-755 ◽  
pp. 950-954
Author(s):  
Mohd Faisal Taha ◽  
Anis Suhaila Shuib ◽  
Maizatul Shima Shaharun ◽  
Azry Borhan

An attempt was made to study the potential of rice husk as an alternative cheap precursor for activated carbon to remove Ni2+ from aqueous solution. Rice husk was treated chemically (with NaOH) and physically (carbonization) to prepare rice husk based activated carbon (RHAC). The textural properties of RHAC, i.e. surface area (255 m2/g) and pore volume (0.17 cm2/g), were determined by N2 adsorption using Brunauer-Emmett-Teller (BET) surface analyzer. RHAC was also characterized for its morphology and its elemental compositions. The adsorption studies for the removal of Ni2+ from aqueous solution were carried out using different dosage of RHAC as adsorbent as a function of varied contact time. The concentration of Ni2+ was determined by atomic absorption spectrometer (AAS). The results obtained from adsorption studies indicate good potential of rice husk as a cheap precursor to produce activated carbon for the removal of Ni2+ from aqueous solution. The equilibrium data from adsorption studies fitted well the of Langmuir and Freundlich isotherm models.


2011 ◽  
Vol 413 ◽  
pp. 38-41
Author(s):  
Xiu Ling Song ◽  
Hui Qian

After activated carbon is oxidized and modified with nitric acid (1:1), its cation exchange capacity can amount to 1.840 mmol • g-1. The modified activated carbon is used as adsorbent for the treatment of Cr (Ⅵ)-containing wastewater at room temperature, and its removal mechanism is discussed in this paper. It is shown that: when the pH value of the aqueous solution being 2.5-3.0;the adsorption time being 3.0h, the removal rate of Cr (Ⅵ) in the aqueous solution can reach 97% and its adsorption capacity can amount to 45.66 mg • g-1. From the results, it can be also seen that the adsorption curve to chromium in wastewater by the modified activated carbon better meets the Freundlich isotherm, and ion exchange adsorption mainly does its work.


2016 ◽  
Vol 17 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Shreeya Kalidindi ◽  
Mounica Vecha ◽  
Arkamitra Kar ◽  
Trishikhi Raychoudhury

Several studies have focused on the application of layered double hydroxide or nanoparticle based adsorbent for removing fluoride. The objectives of this study are to impregnate aluminum (Al) and cerium (Ce) within the pore spaces of activated carbon (AC) for removal of fluoride from water and to evaluate the partitioning behavior of fluoride by the double-metal-AC composite. To achieve the objectives, combined oxides/hydroxides of Al and Ce were impregnated within the pore spaces of AC under varying pH, metal concentration, and synthesis temperature. The fluoride removal by different composite was evaluated, and the best performing composite was selected for equilibrium sorption experiments and kinetic tests. The effect of pH on fluoride removal was assessed. Overall it was observed that impregnation of a small amount of metal (0.05 mol/L Al-Ce) can enhance the fluoride removal efficiency, compared to unmodified AC. Sorption of the best performing composite follows the Freundlich isotherm model. The maximum fluoride sorption capacity was estimated as 3.05 mg F−/g of composite. The rate of sorption by the selected composite is reasonably fast (3.6/h). Furthermore, within a wide range of pH (5–10), removal of fluoride was observed to be consistent.


Author(s):  
Ernesto Jr. S. Cajucom ◽  
◽  
Lolibeth V. Figueroa ◽  

This study was carried out to investigate the efficiency of raw pili shell (RPS) and the surface modified pili shell using EDTA (EMPS) and oxalic acid (OMPS). A comparative study on the adsorption capacity of the adsorbents was performed against lead (Pb2+) from aqueous solution. The adsorbents were characterized by FTIR, which showed higher peak of adsorption bands of carboxylic groups on the acid modified pili shells. Scanning electron microscope orSEM was also used to describe the surface morphology of the adsorbents. The linear form of Langmuir and Freundlich models were applied to represent adsorption data. The calculated equilibrium data of Pb (II) best fitted to Langmuir compare to Freundlich isotherm model with maximum adsorption capacity (qmax) of 27.03 mg/g and 45.45 mg/g using EMPS and OMPS, respectively. Kinetic sorption models were used to determine the adsorption mechanism and the kinetic data of all the adsorbents correlated (R2=1) wellwith the pseudo second order kinetic model. Among the three adsorbents, OMPS shown higher percent removal of lead compared to RPS and EMPS. The large adsorption capacity rate indicated that chemically modified pili shell in present study has great potential to be used as a cost-effective adsorbent for the removal of lead ions from the water.


2005 ◽  
Vol 23 (2) ◽  
pp. 145-160 ◽  
Author(s):  
N. Vennilamani ◽  
K. Kadirvelu ◽  
Y. Sameena ◽  
S. Pattabhi

Activated carbon (AC) prepared from sago waste was characterized and used to remove chromium(VI) ions from aqueous solution and industrial effluent by adsorption methods using various conditions of agitation time, metal ion concentration, adsorbent dosage particle size and pH. Surface modification of the carbon adsorbent with a strong oxidizing agent like concentrated H2SO4 generates more active adsorption sites on the solid surface and pores for metal ion adsorption. Adsorption of the metal ion required a very short time and led to quantitative removal. Both the Langmuir and Freundlich isotherm models could describe the adsorption data. The calculated values of Q0 and b were 5.78 mg/g and 1.75 1/min, respectively. An effective adsorption capacity was noted for particle sizes in the range 125–250 μm at room temperature (30 ± 2°C) and an initial pH of 2.0 ± 0.2. The specific surface area of the activated carbon was determined and its properties studied by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FT-IR). These studies revealed that AC prepared from sago waste is suitable for the removal of Cr(VI) ions from both synthetic and industrial effluents.


2018 ◽  
Vol 7 (3.18) ◽  
pp. 91 ◽  
Author(s):  
Khairul Anwar Mohamad Said ◽  
Nor Zakirah Ismail ◽  
Ramizah Liyana Jama'in ◽  
Nurul Ain Mohamed Alipah ◽  
Norsuzailina Mohamed Sutan ◽  
...  

The aim of this study was to investigate the application of membrane equipped activated carbon for heavy metal removal. An adsorption capacity of the activated carbon inside membrane matrix was performed against environmentally problematic ions specifically Pb2+, in aqueous solution. The adsorption process was examined by Temkin and Freundlich isotherm. From the SEM observation, membrane exhibit sponge-like structure with dense micro-void formation across the matrix. This phenomenon was usually observed with membrane mixed with polyethyleneimine. For the adsorption studies, it is shown that Freundlich isotherm show better fit based on R2 value of 0.9893 with Temkin isotherm fitted with R2 of 0.9009. Through the fitted model, the adsorption occur on the surface of activated carbon are possibly multilayer type adsorption based on theory by Freundlich isotherm and fall under non-ideal reversible adsorption.  


2020 ◽  
Vol 82 (7) ◽  
pp. 1484-1494
Author(s):  
Peter Emmanuel Ebili ◽  
Manase Auta ◽  
Kehinde Shola Obayomi ◽  
Joseph Onyebuchi Okafor ◽  
Muibat Diekola Yahya ◽  
...  

Abstract Tea waste was carbonized at 400 °C for 45 min and modified with potassium hydroxide (KOH), to enhance the active sites for the adsorption of antibiotics. The developed tea waste activated carbon (TWAC) was used as a novel eco-friendly and cost-effective adsorbent for metronidazole (MZN) removal from aqueous solution. The textural and surface properties of the adsorbent were determined using Brunauer-Emmett-Teller (BET) and FT-Raman analysis. The BET surface was found to have increased from 24.670 to 349.585 after carbonization and KOH modification. The batch experimental parameters were optimized and equilibrium time was found to be 75 min. Linear and non-linear models were carried out on the adsorption isotherm and kinetics to determine the best fit for the adsorption data. The adsorption equilibrium data were well fitted by the Freundlich isotherm and pseudo-second order models, with higher regression correlation (R2) and smaller chi-square (χ2), as predicted by the non-linear model. The thermodynamic results revealed the adsorption of MZN as spontaneous, physical, and consistently exothermic in character. The activation energy value of 7.610 kJ/mol further revealed that the adsorption process is dominated majorly by physical adsorption. The removal of MZN onto TWAC was best described by the non-linear adsorption isotherm and kinetics model.


2019 ◽  
Vol 31 (6) ◽  
pp. 1343-1348
Author(s):  
K.V. SATHASIVAM ◽  
N.K. FULORIA ◽  
S. FULORIA ◽  
P.J. DARSHENEE ◽  
R. XAVIER ◽  
...  

Present study was intended to explore the biosorption of Cu(II) and Pb(II) ions in aqueous solution using activated carbon biosynthesized from macro-algae Kappaphycus alvarezii under different experimental parameters. Activated carbon was produced via zinc chloride chemical activation method. The effect of parameters such as pH, temperature over biosorption, amount of adsorbents, initial Cu(II) and Pb(II) aqueous concentration, and contact time were studies. The pH 4.0 for adsorption of Cu(II) and Pb(II), and metal ions uptake contact time of 60 min were considered as optimum. Equilibrium data of biosorption were analyzed by models of Langmuir and Freundlich isotherm at different initial Cu(II) and Pb(II) aqueous solutions concentration. Fruendlich adsorption isotherm model fitted well into biosorption data with a regression value of 0.9986. Thermodynamic parameters such as change in change of enthalpy (ΔHº), change of entropy (ΔSº) and Gibbs free energy (ΔGº) were also determined.


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