scholarly journals Removal of chromium from synthetic wastewater by adsorption onto Ethiopian low-cost Odaracha adsorbent

2020 ◽  
Vol 10 (11) ◽  
Author(s):  
Yohanis Birhanu ◽  
Seyoum Leta ◽  
Getachew Adam
Keyword(s):  
Contact Time ◽  
Low Cost ◽  
Cost Effective ◽  
Green Technology ◽  
Synthetic Wastewater ◽  
Batch Adsorption ◽  
Experimental Conditions ◽  
Wide Range ◽  
Cr Concentration ◽  
Adsorbent Dose

AbstractNowadays, Cr-loaded wastewater released from industrial activities pose an increasing risk to human health and the environment. Adsorption processes have been widely used for the removal of chromium from the waste stream. In this regard, natural adsorbents are the most preferable and cost-effective methods. In this study, the efficiency of Odaracha adsorbent as a novel green technology in the removal of chromium from synthetic wastewater is analyzed. Batch adsorption experiments were conducted to evaluate the effect of contact time, pH, adsorbent dose, and initial concentration of adsorbate on Cr removal. The surface morphology of Odaracha adsorbent was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. Experimental results showed that Odaracha adsorbent could perform effectively in a wide range of experimental conditions. However, in optimum experimental conditions, such as 180-min contact time, pH 3, and 15 g/L of adsorbent dose Odaracha adsorbent removes 94.68% of Cr from an aqueous solution having 110 mg/L of Cr concentration.

scholarly journals Application of treated eggplant peel as a low-cost adsorbent for water treatment toward elimination of Pb2+: Kinetic modeling and isotherm study

2018 ◽  
Vol 36 (3-4) ◽  
pp. 1112-1143 ◽  
Author(s):  
Mohammad Hossein Karimi Darvanjooghi ◽  
Seyyed Mohammadreza Davoodi ◽  
Arzu Y Dursun ◽  
Mohammad Reza Ehsani ◽  
Iman Karimpour ◽  
...  
Keyword(s):  
Contact Time ◽  
Low Cost ◽  
Standard Free Energy ◽  
Chemical Properties ◽  
Entropy Change ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Standard Entropy ◽  
Adsorption Parameters ◽  
Adsorbent Dose

In this study, treated eggplant peel was used as an adsorbent to remove Pb2+ from aqueous solution. For this purpose batch adsorption experiments were performed for investigating the effect of contact time, pH, adsorbent dose, solute concentrations, and temperature. In order to assess adsorbent’s physical and chemical properties, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used. The results showed that the adsorption parameters for reaching maximum removal were found to be contact time of 110 min, adsorbent dose of 0.01 g/ml, initial lead(II) concentration of 70 ppm, pH of 4, and temperature of 25°C. Moreover, for the experiments carried out at pH > 4 the removal occurred by means of significant precipitation as well as adsorption. Furthermore, these results indicated that the adsorption followed pseudo-second-order kinetics model implying that during the adsorption process strong bond between lead(II) and chemical functional groups of adsorbent surface took place. The process was described by Langmuir model (R2 = 0.99; maximum adsorption capacity 88.33 mg/g). Also thermodynamics of adsorption was studied at various temperatures and the thermodynamic parameters including equilibrium constant (K), standard enthalpy change, standard entropy change, and standard free energy changes were obtained from experimental data.

scholarly journals Hen feather a bio-waste material for adsorptive removal of methyl red dye from aqueous solutions

2021 ◽  
Author(s):  
Samina Zaman ◽  
Md. Nayeem Mehrab ◽  
Md. Shahnul Islam ◽  
Gopal Chandra Ghosh ◽  
Tapos Kumar Chakraborty
Keyword(s):  
Aqueous Solutions ◽  
Contact Time ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Methyl Red ◽  
Experimental Conditions ◽  
Potential Applicability ◽  
Pseudo Second Order ◽  
Red Dye ◽  
Adsorbent Dose

Abstract This study investigates the potential applicability of hen feather (HF) to remove methyl red (MR) dye from aqueous solution with the variation of experimental conditions: contact time (1–180 min), pH (4–8), initial dye concentration (5–50 mg/L) and adsorbent dose (3–25 g/L). Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) evaluate the surface morphology and chemistry of HF, respectively. The maximum removal of MR by HF was 92% when the optimum conditions were initial MR dye concentration 05 mg/L, pH 4.0, adsorbent dose 07.0 g/L and 90.0 min equilibrium contact time. Langmuir isotherm (R2 = 0.98) was more suited than Freundlich isotherm (R2 = 0.96) for experimental data, and the highest monolayer adsorption capacity was 6.02 mg/g. The kinetics adsorption data fitted well to pseudo-second-order model (R2 = 0.999) and more than one process were involved during the adsorption mechanism but film diffusion was the potential rate-controlling step. The findings of the study show that HF is a very effective and low-cost adsorbent for removing MR dye from aqueous solutions.

scholarly journals Synthesis and characterization of aluminum-based adsorbent and application in fluoride removal from aqueous solution

2020 ◽  
Vol 10 (1) ◽  
pp. 46-61 ◽  
Author(s):  
Jihane Assaoui ◽  
Zineb Hatim ◽  
Abdelmoula Kheribeche
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Fluoride Concentration ◽  
Infrared Spectrometry ◽  
Fluoride Removal ◽  
Batch Adsorption ◽  
X Ray ◽  
Wide Range ◽  
Adsorbent Dose

A novel adsorbent was obtained by a facile precipitation method and was used for fluoride removal from aqueous solution. Mineralogical and physicochemical characterization of the adsorbent was carried out by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Energy Dispersive X-Ray attached to Scanning Electron Microscopy (SEM-EDX), BET Specific Surface Area(SSAN2BET) analysis and Fourier-Transform Infrared Spectrometry (FTIR). The effect of various operational parameters such as contact time, initial fluoride concentration, (20-160 mg L-1) adsorbent dose (1-6 g L-1) and initial pH solution (3-11) was evaluated in batch procedures at room temperature (25±2°C). The results of the batch adsorption experiments proved that 24 h of contact time was sufficient for attaining equilibrium. The maximum wastewater defluoridation (84.91%) was obtained for 40 mg L-1 and 3 g L-1 of initial fluoride concentration and adsorbent dose, respectively. It appears that there was no significant effect on the F- removal over a wide range of pH 3-11. Kinetic studies revealed that fluoride adsorption fitted well to pseudo-second-order. The adsorption isotherm of fluoride sorption indicated that the maximum adsorption capacity was noted to be 43.29 mg g-1. Batch adsorption data was better described by Langmuir isotherm confirming monolayer adsorption with homogenous distribution of active sites and without interaction between adsorbed molecules. The obtained results indicated that the ion exchange is probably the main mechanism involved in the F- adsorption by the aluminium-based adsorbent.

scholarly journals Biosorption of Azo Dye (Maxilon Red and Everzol Red) on to Natural and Modified Waste Sludge

2017 ◽  
Vol 20 (1) ◽  
pp. 25-32 ◽  
Keyword(s):  
Azo Dye ◽  
Contact Time ◽  
Low Cost ◽  
Experimental Conditions ◽  
Waste Sludge ◽  
Biosorption Process ◽  
Biosorption Mechanism ◽  
Wide Range ◽  
Initial Ph ◽  
Pseudo Second Order

A wide range of technologies has been developed for the removal of dyes from wastewaters to decrease their environmental impact. Wastewater containing dyes is generally treated using more than one process such as adsorption/biosorption. In this study, effects of initial pH (2-8), initial azo dye concentration (Co:25-200 mg/l), contact time (tc:2.5-1440 min) and amount of waste sludge (m:1-15 g/l) were studied by natural and modified dried waste aerobic sludge (WS) in a lab-scale batch study and also optimized by employing response surface methodology (RSM)-Box-Behnken Model for Maxilon Red GRL(MRGRL) and Everzol Red (ER) removal from wastewaters. The optimum experimental conditions were found to be pH=5, Co= 112.5 mg/l, tc= 180 min. and m= 15g/l for dyes and MRGRL and ER removal was determined as about 97% and 95.85%, respectively. The results clearly showed that amount of WS and contact time are the most important parameters for color removal. FTIR and SEM (scanning electron microscope) images were used to understand morphology and structural character of WS and after biosorption process. D-R biosorption isotherm model was used in order to determine type of biosorption mechanism. The E value of D-R isotermisotherm model was found to be 7.071 for both dye. Pseudo-second order and intraparticle diffusion (Weber-Morris) models were suitable for biosorption kinetics. 0,1 M HCl and NaOH were used for desorption studies. Effect of ionic strength (NaCl) was not observed between 0,5-1 mol/L NaCl on to biosorption efficiency. WS (biowaste), Natural or modified, one of the low-cost biosorbent, can be used for removal of azo dye from wastewaters.

scholarly journals Kinetics and isotherm modeling of Pb(II) and Cd(II) sequestration from polluted water onto tropical ultisol obtained from Enugu Nigeria

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Theresa C. Umeh ◽  
John K. Nduka ◽  
Kovo G. Akpomie
Keyword(s):  
Metal Ions ◽  
Low Cost ◽  
Water Environment ◽  
Standard Technique ◽  
Soil Surface ◽  
Cost Effective ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Lead And Cadmium ◽  
Pseudo Second Order

AbstractDeterioration in soil–water environment severely contributed by heavy metal bioavailability and mobility on soil surface and sub-surface due to irrational increase in wastewater discharge and agrochemical activities. Therefore, the feasibility of adsorption characteristics of the soil is paramount in curbing the problem of micropollutant contamination in the farming vicinity. Soil from a farming site in a populated area in Enugu, Nigeria was collected and tested to measure the lead and cadmium contents using atomic absorption spectrophotometer (AAS). The adsorption potency of the ultisol soil was estimated for identifiable physicochemical properties by standard technique. The mean activity concentration of Pb2+ and Cd2+ was 15.68 mg/kg and 3.01 mg/kg. The pH, temperature, metal concentration and contact time adsorptive effect on the Pb2+ and Cd2+ uptake was evaluated by batch adsorption technique. The Langmuir, Freundlich and Temkin models were fitted into equilibrium adsorption data and the calculated results depict a better and satisfactory correlation for Langmuir with higher linear regression coefficients (Pb2+, 0.935 and Cd2+, 0.971). On the basis of sorption capacity mechanism of the soil, pseudo-second-order model best described the kinetics of both metal ions retention process. The results of the present study indicated that the soil being a low cost-effective adsorbent can be utilized to minimize the environmental risk impact of these metal ions.

scholarly journals Comparative studies on the removal of copper (II) by Ulva fasciata activated carbon and commercially activated carbon

2012 ◽  
Vol 14 (4) ◽  
pp. 88-94 ◽  
Author(s):  
R.P. Suresh Jeyakumar ◽  
V. Chandrasekaran
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Synthetic Wastewater ◽  
Batch Adsorption ◽  
First Order ◽  
Ulva Fasciata ◽  
Adsorption Data ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Adsorbent Dose

Abstract In this work, the efficiency of Ulva fasciata sp. activated carbons (CCUC, SCUC and SSUC) and commercially activated carbon (CAC) were studied for the removal of Cu (II) ions from synthetic wastewater. Batch adsorption experiments were carried out as a function of pH, contact time, initial copper concentration and adsorbent dose. The percentage adsorption of copper by CCUC, SSUC, SCUC and CAC are 88.47%, 97.53%, 95.78% and 77.42% respectively. Adsorption data were fitted with the Langmuir, Freundlich and Temkin models. Two kinetic models pseudo first order and the pseudo second order were selected to interpret the adsorption data.

scholarly journals From Waste to Biosorbent: Removal of Congo Red from Water by Waste Wood Biomass

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 279 ◽  
Author(s):  
Marija Stjepanović ◽  
Natalija Velić ◽  
Antonela Galić ◽  
Indira Kosović ◽  
Tamara Jakovljević ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Congo Red ◽  
Contact Time ◽  
Synthetic Wastewater ◽  
Wood Biomass ◽  
Waste Wood ◽  
Biosorption Capacity ◽  
Biosorption Process ◽  
Cr Concentration ◽  
Cr Removal

The aim of the study was to screen the waste wood biomass of 10 wood species as biosorbents for synthetic dye Congo Red (CR) removal from water and to single out the most efficient species for further batch biosorption experiments. Euroamerican poplar (EP), the most efficient species achieving 71.8% CR removal and biosorption capacity of 3.3 mg g−1, was characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR). Different factors affecting the biosorption process were investigated: initial biosorbent concentration (1–10 g dm−3), contact time (5–360 min), initial CR concentration (10–100 mg dm−3), and the initial pH (pH = 4–9). The results showed that CR removal efficiency increased with the increase of biosorbent concentration and contact time. Increase of initial CR concentration led to an increase of the biosorption capacity, but also a decrease of CR removal efficiency. The highest CR removal efficiency was achieved at pH = 4, while at pH = 9 a significant decrease was noticed. The percentage of CR removal from synthetic wastewater was 18.6% higher than from model CR solution. The Langmuir model fitted well the biosorption data, with the maximum biosorption capacity of 8 mg g−1. The kinetics data were found to conform to the pseudo-second-order kinetics model.

Granular activated carbon (GAC) adsorption in tertiary wastewater treatment: experiments and models

2003 ◽  
Vol 47 (1) ◽  
pp. 113-120 ◽  
Author(s):  
D.S. Chaudhary ◽  
S. Vigneswaran ◽  
V. Jegatheesan ◽  
H.H. Ngo ◽  
H. Moon ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Carbon ◽  
Fixed Bed ◽  
Granular Activated Carbon ◽  
Developed Countries ◽  
Synthetic Wastewater ◽  
Batch Adsorption ◽  
Model Parameters ◽  
Wide Range ◽  
Gac Adsorption

Wastewater treatment has always been a major concern in the developed countries. Over the last few decades, activated carbon adsorption has gained importance as an alternative tertiary wastewater treatment and purification process. In this study, granular activated carbon (GAC) adsorption was evaluated in terms of total organic carbon (TOC) removal from low strength synthetic wastewater. This paper provides details on adsorption experiments conducted on synthetic wastewater to develop suitable adsorption isotherms. Although the inorganics used in the synthetic wastewater solution had an overall unfavourable effect on adsorption of organics, the GAC adsorption system was found to be effective in removing TOC from the wastewater. This study showed that equation of state (EOS) theory was able to fit the adsorption isotherm results more precisely than the most commonly used Freundlich isotherm. Biodegradation of the organics with time was the most crucial and important aspect of the system and it was taken into account in determining the isotherm parameters. Initial organic concentration of the wastewater was the determining factor of the model parameters, and hence the isotherm parameters were determined covering a wide range of initial organic concentrations of the wastewater. As such, the isotherm parameters derived using the EOS theory could predict the batch adsorption and fixed bed adsorption results of the multi-component system successfully. The isotherm parameters showed a significant effect on the determination of the mass transfer coefficients in batch and fixed bed systems.

scholarly journals Batch Sorption Experiments: Langmuir and Freundlich Isotherm Studies for the Adsorption of Textile Metal Ions onto Teff Straw (Eragrostis tef) Agricultural Waste

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mulu Berhe Desta
Keyword(s):  
Heavy Metals ◽  
Metal Ions ◽  
Contact Time ◽  
Metal Ion ◽  
Low Cost ◽  
Agricultural Waste ◽  
Equilibrium Concentration ◽  
Eragrostis Tef ◽  
Batch Adsorption ◽  
Textile Effluents

Adsorption of heavy metals (Cr, Cd, Pb, Ni, and Cu) onto Activated Teff Straw (ATS) has been studied using batch-adsorption techniques. This study was carried out to examine the adsorption capacity of the low-cost adsorbent ATS for the removal of heavy metals from textile effluents. The influence of contact time, pH, Temperature, and adsorbent dose on the adsorption process was also studied. Results revealed that adsorption rate initially increased rapidly, and the optimal removal efficiency was reached within about 1 hour. Further increase in contact time did not show significant change in equilibrium concentration; that is, the adsorption phase reached equilibrium. The adsorption isotherms could be fitted well by the Langmuir model. The value in the present investigation was less than one, indicating that the adsorption of the metal ion onto ATS is favorable. After treatment with ATS the levels of heavy metals were observed to decrease by 88% (Ni), 82.9% (Cd), 81.5% (Cu), 74.5% (Cr), and 68.9% (Pb). Results indicate that the freely abundant, locally available, low-cost adsorbent, Teff straw can be treated as economically viable for the removal of metal ions from textile effluents.

scholarly journals A Novel Adaptive Pixels Segmentation Algorithm for Pavement Crack Detection

2021 ◽  
Author(s):  
Nima Safaei ◽  
Omar Smadi ◽  
Babak Safaei ◽  
Arezoo Masoud
Keyword(s):  
Crack Detection ◽  
Low Cost ◽  
Local Level ◽  
Cost Effective ◽  
Segmentation Algorithm ◽  
Pavement Maintenance ◽  
Detection Systems ◽  
Wide Range ◽  
Cost Efficient ◽  
Pavement Crack Detection

<p>Cracks considerably reduce the life span of pavement surfaces. Currently, there is a need for the development of robust automated distress evaluation systems that comprise a low-cost crack detection method for performing fast and cost-effective roadway health monitoring practices. Most of the current methods are costly and have labor-intensive learning processes, so they are not suitable for small local-level projects with limited resources or are only usable for specific pavement types.</p> <p>This paper proposes a new method that uses an improved version of the weighted neighborhood pixels segmentation algorithm to detect cracks in 2-D pavement images. This method uses the Gaussian cumulative density function as the adaptive threshold to overcome the drawback of fixed thresholds in noisy environments. The proposed algorithm was tested on 300 images containing a wide range of noise representative of different noise conditions. This method proved to be time and cost-efficient as it took less than 3.15 seconds per 320 × 480 pixels image for a Xeon (R) 3.70 GHz CPU processor to determine the detection results. This makes the model a perfect choice for county-level pavement maintenance projects requiring cost-effective pavement crack detection systems. The validation results were promising for the detection of low to severe-level cracks (Accuracy = 97.3%, Precision = 79.21%, Recall= 89.18% and F<sub>1</sub> score = 83.9%).</p>

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