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).

Utilisation of Biomass and Hybrid Biochar from Elephant Grass and Low Density Polyethylene for the Competitive Adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) from Aqueous Media

2020 ◽  
Vol 13 ◽  
Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Contact Time ◽  
Competitive Adsorption ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Polluted Water ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Elephant Grass

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.

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.

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 Nitration of Jharia basin coals, India: a study of structural modifications by XRD and FTIR techniques

2021 ◽  
Author(s):  
Prabal Boral ◽  
Atul K. Varma ◽  
Sudip Maity
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Linear Relationship ◽  
Glacial Acetic Acid ◽  
Vitrinite Reflectance ◽  
Aqueous Media ◽  
Interlayer Spacing ◽  
Acetic Acid Medium ◽  
X Ray ◽  
The Media

AbstractFour coal samples from Jharia basin, India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical, petrographic and spatial structure of the organic mass by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. X-ray parameters of coal like interlayer spacing (d002), crystallite size (Lc), aroamticity (fa), average number of aromatic layers (Nc), and coal rank (I26/I20) have been determined using profile-fitting software. Considerable variation is observed in treated coals in comparison to the demineralized coals. The d002 values of treated coals have increased in both the media showing increase in disordering of organic moieties. A linear relationship has been observed between d002 values with the volatile matter of the coals. Similarly, the d002 values show linear relationship with Cdmf contents for demineralized as well as for the treated coals in both the media. The Lc and Nc values have decreased in treated coals corresponding to demineralized coals. The present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity (fa) increases with increase in rank and shows a linear relationship with the vitrinite reflectance. The corresponding I26/I20 values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous medium. FTIR studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals (SMCs) in both the media, the corresponding bands at 1550–1490 and 1355–1315 cm−1 respectively. FTIR study confirms that nitration is the predominant phenomenon, though, oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form SMCs. In comparison to raw coals, the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials.

scholarly journals Investigation of Heavy Metal Effects on the Anaerobic Co-Digestion Process of Waste Activated Sludge and Septic Tank Sludge

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Quang-Minh Nguyen ◽  
Duy-Cam Bui ◽  
Thao Phuong ◽  
Van-Huong Doan ◽  
Thi-Nham Nguyen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Cod Removal ◽  
Septic Tank ◽  
Waste Activated Sludge ◽  
Digestion Process ◽  
Cod Removal Efficiency

The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) > Zn > Cr > Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

Enhancing the soil heavy metals removal efficiency by adding HPMA and PBTCA along with plant washing agents

2017 ◽  
Vol 339 ◽  
pp. 33-42 ◽  
Author(s):  
Yaru Cao ◽  
Shirong Zhang ◽  
Guiyin Wang ◽  
Ting Li ◽  
Xiaoxun Xu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Removal Efficiency ◽  
Heavy Metals Removal ◽  
Soil Heavy Metals ◽  
Metals Removal

Synthesis and Infrared Spectrum Characterization of Phenylalanine Chelated Calcium Complex

2011 ◽  
Vol 396-398 ◽  
pp. 1549-1553
Author(s):  
Yu Qi Wu ◽  
Lian Jin Weng ◽  
Yuan Yuan Han ◽  
Xin Yang ◽  
Di Geng
Keyword(s):  
Infrared Spectrum ◽  
Chelate Ring ◽  
Uniform Design ◽  
Water System ◽  
Experimental Result ◽  
Molar Ratio ◽  
Optimal Parameters ◽  
Single Factor ◽  
Preparation Conditions

The preparation conditions in the water system of phenylalanine chelated calcium complex have been evaluated though single-factor tests and optimized by uniform design. Then the optimal parameters were obtained as follows: reaction temperature is 40 °C, reaction time is 182 min, the molar ratio of phenylalanine to calcium is 4.3 and pH = 9.0. Under the best conditions, the experimental result gives chelating rate = 87.40% that is 17.12% lower than the prediction = 104.52%.The infrared spectrum characterization has confirmed the formation of phenylalanine-Ca2+ chelates and the existence of chelate ring.

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