scholarly journals REMOVAL OF HEAVY METALS FROM REFINERIES WASTEWATER

2021 ◽  
Vol 25 (Special) ◽  
pp. 3-97-3-107
Author(s):  
Zainab J. Shadhan ◽  
◽  
Mohammed N. Abbas ◽  
Keyword(s):  
Activated Carbon ◽  
Equilibrium Concentration ◽  
Adsorption Method ◽  
Batch Mode ◽  
Northern Iraq ◽  
Oil Refineries ◽  
A Value ◽  
Removal Of Heavy Metals ◽  
Acidic Function ◽  
Equilibrium Concentrations

In this study, the adsorption method was investigated for removing vanadium (V+5), nickel (Ni+2) and cadmium (Cd+2) ions from aqueous solutions contaminated with these metals, which simulate the polluting metals of the liquid wastewater of oil refineries in three Iraqi refineries, namely the Kirkuk refinery - Kirkuk governorate in northern Iraq, and the Doura refinery - Baghdad in central Iraq and Al-Shuaiba refinery in Basra Governorate, southern Iraq. Three types of pre-prepared common adsorbents were used, which are activated carbon, alumina, and white eggshells in a batch mode unit. The results obtained from the study showed that 5 was the best acidic function (pH) for removing vanadium and cadmium by using all adsorbent materials, while the acidic function with a value of 6 was the optimum in the case of nickel. Likewise, the equilibrium concentration with the activated carbon only reached 150 ppm for vanadium and cadmium and 100 ppm for elemental nickel. The nickel equilibrium concentration reached 90 and 75 ppm using alumina and white eggshells respectively. The equilibrium concentrations of vanadium were 100 for the rest of the substances. The results obtained also showed that increasing the agitation speed leads to enhancing the removal efficiency within less than 400 rpm and with a best contact time was 150 minute under ambient temperature and with an amount of adsorbent ranged between 0.3 - 0.7 g of different adsorbent.

scholarly journals Adsorption of Hexavalent Chromium and Divalent Lead Ions on the Nitrogen-Enriched Chitosan-Based Activated Carbon

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1907
Author(s):  
Fatma Hussain Emamy ◽  
Ali Bumajdad ◽  
Jerzy P. Lukaszewicz
Keyword(s):  
Heavy Metal ◽  
Activated Carbon ◽  
Metal Ions ◽  
Metal Removal ◽  
High Surface ◽  
Heavy Metal Removal ◽  
High Surface Area ◽  
Kinetics Of Adsorption ◽  
Removal Of Heavy Metals ◽  
Pseudo Second Order

Optimizing the physicochemical properties of the chitosan-based activated carbon (Ch-ACs) can greatly enhance its performance toward heavy metal removal from contaminated water. Herein, Ch was converted into a high surface area (1556 m2/g) and porous (0.69 cm3/g) ACs with large content of nitrogen (~16 wt%) using K2CO3 activator and urea as nitrogen-enrichment agents. The prepared Ch-ACs were tested for the removal of Cr(VI) and Pb(II) at different pH, initial metal ions concentration, time, activated carbon dosage, and temperature. For Cr(VI), the best removal was at pH = 2, while for Pb(II) the best pH for its removal was in the range of 4–6. At 25 °C, the Temkin model gives the best fit for the adsorption of Cr(VI), while the Langmuir model was found to be better for Pb(II) ions. The kinetics of adsorption of both heavy metal ions were found to be well-fitted by a pseudo-second-order model. The findings show that the efficiency and the green properties (availability, recyclability, and cost effectiveness) of the developed adsorbent made it a good candidate for wastewaters treatment. As preliminary work, the prepared sorbent was also tested regarding the removal of heavy metals and other contaminations from real wastewater and the obtained results were found to be promising.

scholarly journals Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review

2012 ◽  
Vol 1 (3) ◽  
pp. 75 ◽  
Author(s):  
W.D.P Rengga ◽  
M. Sudibandriyo ◽  
M Nasikin
Keyword(s):  
Activated Carbon ◽  
Activated Carbons ◽  
Chemical Activation ◽  
High Energy ◽  
Hydrogen Gas ◽  
Agricultural Product ◽  
Adsorption Method ◽  
Modified Activated Carbon ◽  
Nano Size ◽  
Formaldehyde Adsorption

Gas storage is a technology developed with an adsorptive storage method, in which gases are stored as adsorbed components on the certain adsorbent. Formaldehyde is one of the major indoor gaseous pollutants. Depending on its concentration, formaldehyde may cause minor disorder symptoms to a serious injury. Some of the successful applications of technology for the removal of formaldehyde have been reported. However, this paper presents an overview of several studies on the elimination of formaldehyde that has been done by adsorption method because of its simplicity. The adsorption method does not require high energy and the adsorbent used can be obtained from inexpensive materials. Most researchers used activated carbon as an adsorbent for removal of formaldehyde because of its high adsorption capacity. Activated carbons can be produced from many materials such as coals, woods, or agricultural waste. Some of them were prepared by specific activation methods to improve the surface area. Some researchers also used modified activated carbon by adding specific additive to improve its performance in attracting formaldehyde molecules. Proposed modification methods on activation and additive impregnated carbon are thus discussed in this paper for future development and improvement of formaldehyde adsorption on activated carbon. Specifically, a waste agricultural product is chosen for activated carbon raw material because it is renewable and gives an added value to the materials. The study indicates that the performance of the adsorption of formaldehyde might be improved by using modified activated carbon. Bamboo seems to be the most appropriate raw materials to produce activated carbon combined with applying chemical activation method and addition of metal oxidative catalysts such as Cu or Ag in nano size particles. Bamboo activated carbon can be developed in addition to the capture of formaldehyde as well as the storage of adsorptive hydrogen gas that supports renewable energy. Keywords: adsorption; bamboo; formaldehyde; modified activated carbon; nano size particles

scholarly journals Investigating the performance of agricultural wastes and their ashes in removing phenol from leachate in a fixed-bed column

2020 ◽  
Vol 81 (10) ◽  
pp. 2109-2126 ◽  
Author(s):  
Seyed Omid Ahmadinejad ◽  
Seyed Taghi Omid Naeeni ◽  
Zahra Akbari ◽  
Sara Nazif
Keyword(s):  
Activated Carbon ◽  
Large Scale ◽  
Fixed Bed ◽  
Walnut Shell ◽  
Continuous Systems ◽  
Phenol Removal ◽  
Adsorption Method ◽  
Fixed Bed Column ◽  
Saturation Time ◽  
Coconut Shell Activated Carbon

Abstract One of the major pollutants in leachate is phenol. Due to safety and environmental problems, removal of phenol from leachate is essential. Most of the adsorption studies have been conducted in batch systems. Practically, large-scale adsorption is carried out in continuous systems. In this research, the adsorption method has been used for phenol removal from leachate by using walnut shell activated carbon (WSA) and coconut shell activated carbon (CSA) as adsorbents in a fixed-bed column. The effect of adsorbent bed depth, influent phenol concentration and type of adsorbent on adsorption was explored. By increasing the depth of the adsorbent bed in the column, phenol removal efficiency and saturation time increase significantly. Also, by increasing the influent concentration, saturation time of the column decreases. To predict the column performance and describe the breakthrough curve, three kinetic models of Yon-Nelson, Adams-Bohart and Thomas were applied. The results of the experiments indicate that there is a good match between the results of the experiment and the predicted results of the models.

Point Defect Properties from Metal Diffusion Experiments — What Does the Data Really Tell Us?

1997 ◽  
Vol 469 ◽  
Author(s):  
Srinivasan Chakravarthit ◽  
Scott T. Dunham
Keyword(s):  
Point Defect ◽  
Equilibrium Concentration ◽  
Simulation Software ◽  
Published Data ◽  
Vacancy Diffusion ◽  
Metal Diffusion ◽  
Float Zone ◽  
Equilibrium Concentrations ◽  
Parameter Values ◽  
Carbon Concentrations

Point defect properties, including diffusivities and equilibrium concentrations for both interstitials and vacancies, are commonly extracted from metal diffusion experiments, and these values are widely used in process simulation software. However, in many cases, these parameter values were extracted using oversimplified models which ignore interactions between interstitial and vacancy diffusion mechanisms. Questions about the accuracy of these parameters have come from ab-initio defect calculations which conclude that vacancies diffuse faster than interstitials, in contrast with published reports on metal diffusion which find vacancies diffuse much more slowly than interstitials. We have reanalyzed published data for zinc and platinum diffusion and find that it is possible to match all of the data using fast vacancy diffusivity. The most direct evidence for slow vacancy diffusion (and a high equilibrium concentration) comes from platinum diffusion experiments. However, we are able to reproduce these results with fast V diffusion and carbon/interstitial clustering, using carbon concentrations typical of Czochralski and float zone silicon (1016cm−3). We evaluate the effectiveness of metal diffusion experiments in determining point defect parameters, and find that it is not possible to reliably determine both diffusivities and equilibrium concentrations for both interstitials and vacancies from metal diffusion results.

scholarly journals Utilization of Non-Living Microalgae Biomass from Two Different Strains for the Adsorptive Removal of Diclofenac from Water

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1401 ◽  
Author(s):  
Ricardo Coimbra ◽  
Carla Escapa ◽  
Nadyr Vázquez ◽  
Guillermo Noriega-Hevia ◽  
Marta Otero
Keyword(s):  
Activated Carbon ◽  
Experimental Conditions ◽  
Biomass Waste ◽  
Adsorptive Removal ◽  
Microalgae Biomass ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Equilibrium Concentrations ◽  
Different Strains ◽  
Synechocystis Sp

In the present work, the adsorptive removal of diclofenac from water by biosorption onto non-living microalgae biomass was assessed. Kinetic and equilibrium experiments were carried out using biomass of two different microalgae strains, namely Synechocystis sp. and Scenedesmus sp. Also, for comparison purposes, a commercial activated carbon was used under identical experimental conditions. The kinetics of the diclofenac adsorption fitted the pseudo-second order equation, and the corresponding kinetic constants indicating that adsorption was faster onto microalgae biomass than onto the activated carbon. Regarding the equilibrium results, which mostly fitted the Langmuir isotherm model, these pointed to significant differences between the adsorbent materials. The Langmuir maximum capacity (Qmax) of the activated carbon (232 mg∙g−1) was higher than that of Scenedesmus sp. (28 mg∙g−1) and of Synechocystis sp. (20 mg∙g−1). In any case, the Qmax values determined here were within the values published in the recent scientific literature on the utilization of different adsorbents for the removal of diclofenac from water. Still, Synechocystis sp. showed the largest KL fitted values, which points to the affinity of this strain for diclofenac at relative low equilibrium concentrations in solution. Overall, the results obtained point to the possible utilization of microalgae biomass waste in the treatment of water, namely for the adsorption of pharmaceuticals.

scholarly journals Ricinus CommunisPericarp Activated Carbon Used as an Adsorbent for the Removal of Ni(II) From Aqueous Solution

2008 ◽  
Vol 5 (4) ◽  
pp. 761-769 ◽  
Author(s):  
S. Madhavakrishnan ◽  
K. Manickavasagam ◽  
K. Rasappan ◽  
P. S. Syed Shabudeen ◽  
R. Venkatesh ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Activated Carbon ◽  
Contact Time ◽  
Metal Ion ◽  
Ricinus Communis ◽  
Ion Concentration ◽  
Batch Mode ◽  
Adsorption Data ◽  
Initial Ph

Activated carbon prepared from Ricinus communis Pericarp was used to remove Ni(II) from aqueous solution by adsorption. Batch mode adsorption experiments are carried out by varying contact time, metal-ion concentration, carbon concentration and pH to assess kinetic and equilibrium parameters. The adsorption data were modeled by using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity (Qo) calculated from the Langmuir isotherm was 31.15 mg/g of activated carbon at initial pH of 5.0±0.2 for the particle size 125-250 µm.

Removal of heavy metals from aqueous solutions using activated carbon prepared fromCicer arietinum

2010 ◽  
Vol 92 (8) ◽  
pp. 1447-1460 ◽  
Author(s):  
D.K.V. Ramana ◽  
K. Jamuna ◽  
B. Satyanarayana ◽  
B. Venkateswarlu ◽  
M. Madava Rao ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Activated Carbon ◽  
Aqueous Solutions ◽  
Removal Of Heavy Metals

Reduction of COD from Micro-Polluted Water through Adsorption of Activated Carbon-Attapulgite Composite Adsorbent

2010 ◽  
Vol 450 ◽  
pp. 445-448
Author(s):  
Zheng Wang ◽  
Zhao Qian Jing ◽  
Yu Kong ◽  
Wei Shen
Keyword(s):  
Activated Carbon ◽  
Oxygen Demand ◽  
Polluted Water ◽  
Adsorption Model ◽  
Batch Mode ◽  
Composite Adsorbent ◽  
Adsorption Data ◽  
Complete Study ◽  
Ph Range ◽  
Optimum Ph Range

The aim of this study was the assessment of reduction of chemical oxygen demand (COD) from micro-polluted water using activated carbon-attapulgite composite adsorbent prepared using activated carbon and natural attapulgite through compounding, granulation and calcination. The complete study was done in batch mode to investigate the effect of operating parameters. Adsorption of COD was found to be dependent on contact time, pH, temperature and initial COD concentration. Adsorption equilibrium attained within 80 minutes time. The optimum pH range for adsorption of organics was found to be 8. The sorption of organics decreased with rise of temperature because adsorption process was exothermic. The studied adsorption data fitted well to Langmuir adsorption model with the correlation coefficient 0.9947. The activated carbon-attapulgite composite adsorbent in this study shows very good promise for practical applicability on removal of COD from micro-polluted water.

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