Facile nitric acid activation of carob seeds for efficient recovery of heavy metals from water

2020 ◽  
Vol 204 ◽  
pp. 174-188
Author(s):  
M. Farnane ◽  
A. Machrouhi ◽  
M. Khnifira ◽  
M. Barour ◽  
R. Elmoubarki ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Acid Activation ◽  
Efficient Recovery

scholarly journals Optimization of Carob Shells Biomass Activation by Nitric Acid for Heavy Metals Sequestration from Contaminated Water

2021 ◽  
Vol 12 (5) ◽  
pp. 5941-5952
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Removal Efficiency ◽  
Energy Demand ◽  
Aqueous Media ◽  
Experimental Result ◽  
Acid Activation ◽  
Activation Temperature ◽  
Cobalt Ions ◽  
Preparation Conditions

This study reports the use of agro-waste (carob shells) as a precursor for the synthesis of activated carbon by nitric acid activation. The prepared adsorbent was used for the removal of cadmium and cobalt ions from aqueous media. In order to optimize the preparation conditions for the high removal efficiency of heavy metals, the Box-Behnken design was used to correlate activation agent ratio g(HNO3)/g(carbon), reaction time, and activation temperature to the removal efficiency of metals. The experimental result shows that the rise in activation temperature strongly decreases the removal of both metals. This result suggests a low energy demand for the activation of carob shells by HNO3. The sample prepared at optimum conditions was characterized by DRX, SEM, FTIR, and surface groups titrations in order to obtain information on its structural, morphological, and surface properties. It has also been found that equilibrium data are well correlated to the Langmuir model with adsorption capacities of 125.52 and 69.01 mg/g, respectively, for Cd(II) and Co(II).

Recovery of Heavy Metals from the Spent Catalyst of the Hydrotreating Unit (HDT) for the Use of the Impregnation of Supported Catalysts

2018 ◽  
Vol 792 ◽  
pp. 133-139 ◽  
Author(s):  
Toapanta Germania ◽  
Caterine Donoso ◽  
María José Cárdenas ◽  
Amón Bolívar ◽  
Vladimir Ortiz
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Acid Concentration ◽  
Supported Catalysts ◽  
Nitric Acid Concentration ◽  
Added Value ◽  
High Tech ◽  
Spent Catalyst ◽  
X Ray ◽  
Spent Catalysts

Spent catalysts contain metals that have a high added value. From all metals, lanthanum has attracted a lot of attention due to the growing demand in the high-tech. The spent catalyst of the hydrotreatment unit is a material composed of lanthanum-enriched matrix of amorphous aluminosilicates. The experiment was carried out with a spent catalyst with a constant particle size of 90 μm. The treatments were obtained applying of two level factorial design to investigate the effect of following factors: temperature (20 - 60 °C), nitric acid concentration (3 - 6 M), leaching time (1 - 4 h) and percent solids (10 - 20 %). The research is carried out in two steps process: pretreatment of the catalyst and leaching with nitric acid. The leaching results show a yield of lanthanum of 99.44% using the following conditions: temperature (20 °C), nitric acid concentration (3M), leaching time (1 h), percent solids (20%) and 300 rpm. The principal analysis of the spent catalyst was carried out using the X-Ray Fluorescence (XRF) technique, 3.08%, while the percentage of lanthanum recovery in the extract, washing and refining was carried out using the Inductive Coupling Plasma (ICP) technique.

Leaching of Heavy Metals from Municipal Solid Waste Incineration (MSWI) Fly Ash Using Nitric Acid

2012 ◽  
Vol 249-250 ◽  
pp. 918-921 ◽  
Author(s):  
Hai Ying Zhang ◽  
Guo Xian Ma
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Nitric Acid ◽  
Municipal Solid Waste ◽  
Waste Incineration ◽  
Acid Extraction ◽  
Municipal Solid Waste Incineration ◽  
Mswi Fly Ash ◽  
Removal Ratio ◽  
Solid Ratio

The presence of heavy metals in municipal solid waste incineration (MSWI) fly ash is of environmental concern due to their leaching potential in landfill environments. Acid extraction is a conventional method of safe treatment of fly ash. In this work, nitric acid was used as the extraction acid to leach Ni, Zn, Pb and Cu out from the ash. In addition, influence of nitric acid concentration and liquid to solid ratio on removal ratio of the four heavy metals was studied. It was found that removal ratio followed the decreasing sequence of Pb > Cd > Cu > Zn for acid extraction using nitric acid. The optimal extraction condition was 5.3 mol/L of nitric concentration at 20 liquid to solid ratio, which resulted in a removal ratio of 98% for Pb, 86% for Cd, around 73% for Cu and around 42% for Zn.

scholarly journals Bioaccumulation of Some Heavy Metals in Ayre Fish (Sperata Aor Hamilton, 1822), Sediment and Water of Dhaleshwari River in Dry Season

2012 ◽  
Vol 40 (1) ◽  
pp. 147-153 ◽  
Author(s):  
Abu Tweb Abu Ahmed ◽  
Suman Mandal ◽  
Didarul Alam Chowdhury ◽  
Abu Rayhan M Tareq ◽  
M Mizanur Rahman
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Atomic Absorption ◽  
Water Samples ◽  
Dry Weight ◽  
Acid Digestion ◽  
Fish Organs ◽  
Flame Atomic Absorption ◽  
Flame Atomic Absorption Spectrophotometer ◽  
Nitric Acid Digestion

The present study was carried out to determine the level of bioaccumulation of some heavy metals in a freshwater fish Ayre (Sperata aor Hamilton, 1822) collected from Rajfulbaria (23°48?56.36? N and 90°14?54.04? E) of  Dhaleshwari river. Four heavy metals, namely chromium (Cr), copper (Cu), lead (Pb), and cadmium (Cd) were selected for this study. Metal concentrations were   determined by Flame Atomic Absorption Spectrophotometer after nitric acid  digestion of samples. The concentrations of accumulated heavy metals in fish were  also compared with the concentrations of metals in the sediments and waters of  that river. The level of bioaccumulations in different organs of S. aor were determined separately and compared among them. Average bioaccumulation levels  in S. aor were Cr: 1.458 mg/kg, Cu: 31.500 mg/kg, Pb: 18.776 mg/kg and Cd:  0.487 mg/kg of dry weight. The levels of heavy metals in sediments were Cr: 27.393 mg/kg, Cu: 37.450 mg/kg, Pb: 15.797 mg/kg and Cd: 2.083 mg/kg, and in water were Cr: 0.130 ppm, Cu: 0.000 ppm, Pb: 0.201 ppm and Cd: 0.001 ppm.The bioaccumulation of these four heavy metals in fish organs, sediment and  water samples were also compared with FAO approved standard levels and other  related studies, and found that the levels of bioaccumulation in the Dhaleshwari river exceeded all the standard levels. DOI: http://dx.doi.org/10.3329/bjz.v40i1.12904 Bangladesh J. Zool. 40(1):147-153, 2012

scholarly journals Effect of Wastewater Sample Pre-Treatment on Determination of Selected Heavy Metals Using ICP-MS Method

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Iva KOTALOVÁ ◽  
Katrin CALÁBKOVÁ ◽  
Martina NOVÁČKOVÁ ◽  
Silvie DRABINOVÁ ◽  
Silvie HEVIÁNKOVÁ
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Polyaromatic Hydrocarbons ◽  
Treated Wastewater ◽  
Wastewater Sample ◽  
Lead And Cadmium ◽  
Low Concentrations ◽  
Icp Ms ◽  
Pre Treatment

Polychlorinated substances, polyaromatic hydrocarbons, heavy metals and pesticides are among the priority even at low concentrations. The problem, however, is that such low concentrations are impossible to measure using most available methods. This researchfocused on the determination of selected priority substances – heavy metals, namely lead and cadmium, in which the determination ofPb and Cd in wastewater by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was preceded by water sample pre-treatment.The paper deals with the influence of the pre-treatment on the resulting measured values. Two processes were selected as pre-treatmentprocesses. The first pre-treatment procedure was a simple filtration using a filter paper for moderate filtration. As the second procedure, we applied decomposition of the sample by nitric acid in the open system. The pre-treated wastewater samples were subsequentlyexamined using ICP-MS. Based on the obtained results, we can conclude that decomposition of the sample by nitric acid in the opensystem is a more suitable pre-treatment method for water samples

scholarly journals RESEARCH INTO DYNAMICS OF ADSORPTION OF HEAVY METALS ON ACID-ACTIVATED BENTONITE

2021 ◽  
Vol 2 (39) ◽  
pp. 115-124
Author(s):  
D. Stetsenko ◽  
D. Yelatontsev
Keyword(s):  
Heavy Metals ◽  
Chemical Modification ◽  
Flow Rate ◽  
Protective Action ◽  
Acid Activation ◽  
Sorbent Layer ◽  
Layer Height ◽  
Modified Bentonite ◽  
Sorption Column ◽  
Sorption Time

Acid activation of bentonite clay is a common way to obtain porous adsorbents of organic and inorganic substances. Acid activation with preservation of the layered structure is the initial stage of chemical modification. Acid treatment of natural aluminosilicates is aimed at increasing their adsorption capacity and specific surface area. In industrial practice, water treatment of heavy metals is in most cases carried out bypassing the liquid through a fixed layer of backfill. Therefore, in this study, we studied the dynamics of adsorption with the definition of the main characteristics of the process: the speed of the working zone, the coefficient of protective action, the length of the working layer, the loss of protective action time, the duration of the sorption column before leakage. In addition, the establishment of the basic laws of this process can be used to determine the optimal parameters of the sorption material at a given initial characteristic — the length of the layer of the sorption column, the filtration rate. We have studied the possibilities of chemical modification of granular bentonite during acid-salt treatment. Through sorption columns with a height of 0.1; 0.2 and 0.3 m, filled with samples of modified bentonite, were passed model solutions of salts Fe2+, Mn2+, Cu2+ and Cd2+ with a concentration of cations of 0.01 g/dm3. The flow rate of the solution was 0.5; 1.0 and 1.5 m/h. Experimental data show that the optimal sorption values ​​are obtained for samples of modified bentonite: at the same height of the sorbent layer and flow rate, the duration of the layer before skipping in modified samples is 1.25—1.52 times higher than in unmodified ones. It is established that the sorption time before skipping mainly depends on the flow rate and the height of the sorbent layer. Thus, at a layer height of 0.3 m and the same rate of transmission of the solution, the sorption time is up to 3.5 times greater than at a layer height of 0.1 m for all investigated cations.

Leaching of Heavy Metals from Municipal Solid Waste Incineration (MSWI) Fly Ash Using Sulfuric Acid

2012 ◽  
Vol 249-250 ◽  
pp. 922-926 ◽  
Author(s):  
Hai Ying Zhang ◽  
Guo Xian Ma
Keyword(s):  
Heavy Metals ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Nitric Acid ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Waste Incineration ◽  
Acid Extraction ◽  
Municipal Solid Waste Incineration ◽  
Mswi Fly Ash

Municipal solid waste incineration (MSWI) fly ash, a must by-product in incineration of municipal solid waste (MSW) combustion is of environmental concern due to its enrichment in heavy metals (Ni, Cd, Cu and Pb). Extraction using sulfuric acid is a conventional method of safe treatment of fly ash. In this work, influence of sulfuric acid concentration and liquid to solid ratio on removal efficiency of the four heavy metals was investigated. It was found that Removal ratio followed the decreasing sequence of Cd > Cu > Pb >Zn for acid extraction using sulfuric acid, quite different with that sequence of Pb > Cd > Cu > Zn for extraction using nitric acid. Sulfuric acid was efficient in removing Cd and Cu, but less efficient in removing Ni and Zn. Compared with nitric acid, sulfuric acid was less effective in removing Pb, Cu and Ni.

Species Distribution of Heavy Metals in Enhanced Electrokinetic Removal Process

2011 ◽  
Vol 71-78 ◽  
pp. 910-913
Author(s):  
Zhong Hui Xu ◽  
Dong Wei Li ◽  
Xi Peng
Keyword(s):  
Heavy Metals ◽  
Nitric Acid ◽  
Alkali Metal ◽  
Removal Efficiency ◽  
Species Distribution ◽  
Metal Hydroxides ◽  
Visual Minteq ◽  
Main Form ◽  
Removal Of Heavy Metals ◽  
Cathode Area

In this study, in order to evaluate the migration of heavy metals in enhanced electrokinetic removal，visual minteq was adopted to calculate the species distribution of heavy metals in different pH. Most of the heavy metals except arsenic generated the enrichment near the cathode area. Arsenate always existed as anion such as AsO43-、H2AsO4-、HAsO42-. Near the alkaline area ,the main form of heavy metals were alkali metal hydroxides and seriously restricted the migration and removal of heavy metals. The addition of potassium tetroxalate did not change the species distribution of heavy metals obviously.The nitric acid was more efficient than potassium tetroxalate to condition enhanced electrokinetic removal. Nevertheless ,both of two enhancement still need to be impoved to promote the removal efficiency.

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