Electroflotation removal of the dispersed phase of sparingly water-soluble non-ferrous and heavy metals from aqueous media. Effect of the composition of the aqueous medium on the removal efficiency

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.

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

Biointerface Research in Applied Chemistry ◽

10.33263/briac125.59415952 ◽

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).

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Toxicity assessment of free form of heavy metals in aqueous media on earthworm Eudrillus eugeniae

Water Science & Technology ◽

10.2166/wst.2011.240 ◽

2011 ◽

Vol 63 (10) ◽

pp. 2434-2445 ◽

Cited By ~ 2

Author(s):

V. Sharma ◽

P. R. Chaudhari ◽

S. Satyanarayan

Keyword(s):

Heavy Metals ◽

Aqueous Medium ◽

Aqueous Media ◽

Aquatic Organisms ◽

Toxicity Assessment ◽

Free Form ◽

Ionic Form ◽

Aqueous Extracts ◽

Sludge Treatment ◽

Dissolved Form

Metals are found in free and also in combined forms. In order to get information on the effect of free forms of heavy metals on earthworms the aqueous extracts of metals were tested on earthworms both in individual form and also in combined form. Different concentrations, i.e. 1 ppm, 5 ppm, and 10 ppm, were selected arbitrarily and were used in the experiments. Metals like copper, cadmium, chromium, zinc and lead were used. Earthworms’ Eudrillus eugeniae activity, i.e. their response to the toxicity of metals, was monitored continuously for 5 h. It can be concluded that free form/ionic form/dissolved form of heavy metals are more toxic for earthworms, concurrent with findings of workers who have drawn same inference during studies on aquatic organisms. Earthworms can serve as biomarkers for wastewater and sludge treatment studies as they have shown typical adverse body reactions and symptoms altogether different in reaction to each of the metals during aqueous medium studies. It can be inferred that, if earthworms are utilised for treating wastewater and sludges containing these five heavy metals, one can ascertain the presence of individual metal concentrations in the wastewaters and sludges by studying the typical body reactions of earthworms during the treatment.

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Removal of Cu2+ and Zn2+ from aqueous medium using ionic polyacrylamides

Global NEST Journal ◽

10.30955/gnj.001741 ◽

2017 ◽

Vol 19 (2) ◽

pp. 211-216

Keyword(s):

Heavy Metals ◽

Aqueous Medium ◽

Removal Efficiency ◽

Environmental Problem ◽

Metal Removal ◽

Polymer Concentration ◽

Synthetic Wastewater ◽

Zinc Metal ◽

High Concentrations ◽

Ionic Load

The wastewater produced by the galvanoplasty industry is a serious environmental problem due to the high concentrations of heavy metals. In this study polymers were used in ionic flocculation to treat synthetic wastewater containing metals, applying four types of polyacrylamides with different ionic loads as agents to remove copper and zinc. Metal removal efficiency was assessed considering the influence of polymer concentration, ionic load and pH. Selectivity (Cu2+/Zn2+) at different polymer concentrations was also evaluated. The results confirm that polyacrylamide is efficient in treating wastewater containing heavy metals. These experiments exhibited removal efficiency of around 40% and pH= 4,5; however, efficiency was more than 80% with pH= 7.0 under the same conditions, when polyacrylamides with average ionicity were used.

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Layered Double Hydroxides as Effective Adsorbents for U(VI) and Toxic Heavy Metals Removal from Aqueous Media

Journal of Chemistry ◽

10.1155/2013/347178 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

G. N. Pshinko

Keyword(s):

Heavy Metals ◽

Layered Double Hydroxides ◽

Chelating Agents ◽

Ethylenediaminetetraacetic Acid ◽

Aqueous Media ◽

Water Soluble ◽

Toxic Heavy Metals ◽

Metals Removal ◽

The Stability ◽

Double Hydroxides

Capacities of different synthesized Zn,Al-hydrotalcite-like adsorbents, including the initial carbonate [Zn4Al2(OH)12]·CO3·8H2O and its forms intercalated with chelating agents (ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and hexamethylenediaminetetraacetic acid (HMDTA)) and heat-treated form Zn4Al2O7, to adsorb uranium(VI) and ions of toxic heavy metals have been compared. Metal sorption capacities of hydrotalcite-like adsorbents have been shown to correlate with the stability of their complexes with the mentioned chelating agents in a solution. The synthesized layered double hydroxides (LDHs) containing chelating agents in the interlayer space are rather efficient for sorption purification of aqueous media free from U(VI) irrespective of its forms of natural abundance (including water-soluble bi- and tricarbonate forms) and from heavy metal ions. [Zn4Al2(OH)12]·EDTA·nH2O is recommended for practical application as one of the most efficient and inexpensive synthetic adsorbents designed for recovery of both cationic and particularly important anionic forms of U(VI) and other heavy metals from aqueous media. Carbonate forms of LDHs turned out to be most efficient for recovery of Cu(II) from aqueous media withpH0≥7owing to precipitation of Cu(II) basic carbonates and Cu(II) hydroxides. Chromate ions are efficiently adsorbed from water only by calcinated forms of LDHs.

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Self-Healing Polymer-Clay Hybrids by Facile Complexation of a Waterborne Polymer with a Clay

Materials Advances ◽

10.1039/d1ma00099c ◽

2021 ◽

Author(s):

Aranee Pleng Teepakakorn ◽

Makoto Ogawa

Keyword(s):

Vinyl Alcohol ◽

Aqueous Media ◽

Water Soluble ◽

Poly Vinyl Alcohol ◽

Self Healing ◽

Soluble Polymer ◽

Water Soluble Polymer ◽

Smectite Clay

Water-induced self-healing materials were prepared by the hybridization of a water-soluble polymer, poly(vinyl alcohol), with a smectite clay by mixing in an aqueous media and subsequent casting. Without using chemical...

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Dissociation of imino proton(s) of a highly water-soluble metal-free phthalocyanine and determination of its pKa value in water

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424613500235 ◽

2013 ◽

Vol 17 (06n07) ◽

pp. 447-453 ◽

Cited By ~ 2

Author(s):

Hiroaki Isago ◽

Harumi Fujita

Keyword(s):

Aqueous Media ◽

Thermal Reaction ◽

Water Soluble ◽

Acid Dissociation ◽

Acid Dissociation Constant ◽

Metal Free ◽

Imino Proton ◽

Pka Value ◽

Triton X

Dissociation of imino proton(s) in the cavity of the macrocycle of a highly water-soluble, metal-free phthalocyanine ( H 2( H 4 tsppc ); where H 4 tsppc denotes tetrakis{(2′,6′-dimethyl-4′-sulfonic acid)phenoxy}phthalocyaninate) in ethanolic and aqueous solutions has spectrophotometrically been investigated. The spectral changes associated with reaction with NaOH have been found to involve one-proton transfer process in aqueous media while two-protons process in ethanolic media. The acid-dissociation constant of the first imino proton in water (in the presence of Triton X-100) has been determined to be 12.5 ± 0.2 (as pKa) at 25 °C. The doubly deprotonated species in EtOH has been easily converted to its corresponding cobalt(II) derivative by thermal reaction with anhydrous CoCl 2.

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

International Journal of Chemical Engineering ◽

10.1155/2019/5138060 ◽

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.

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

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2017.06.007 ◽

2017 ◽

Vol 339 ◽

pp. 33-42 ◽

Cited By ~ 18

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

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Conventional fluorophore-free dual pH- and thermo-responsive luminescent alternating copolymer

Polymer Chemistry ◽

10.1039/c6py01738j ◽

2016 ◽

Vol 7 (45) ◽

pp. 6895-6900 ◽

Cited By ~ 36

Author(s):

Biswajit Saha ◽

Kamal Bauri ◽

Arijit Bag ◽

Pradip K. Ghorai ◽

Priyadarsi De

Keyword(s):

Aqueous Medium ◽

Free Water ◽

Water Soluble ◽

Alternating Copolymer ◽

Fluorescent Copolymer

Herein, we have designed and synthesized a novel traditional fluorophore-free water-soluble fluorescent copolymer based on a poly(maleimide-alt-styrene) skeleton, which responds to both pH and temperature in aqueous medium.

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