scholarly journals Removal of Chromium(VI) from Contaminated Water Using Untreated Moringa Leaves as Biosorbent

Pollutants ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 51-64
Author(s):  
Chandra Mouli R. Madhuranthakam ◽  
Archana Thomas ◽  
Zhainab Akhter ◽  
Shannon Q. Fernandes ◽  
Ali Elkamel
Keyword(s):  
Removal Efficiency ◽  
Industrial Wastewater ◽  
Metal Removal ◽  
Cost Effective ◽  
Feed Solution ◽  
Hydroxyl Groups ◽  
Docking Simulations ◽  
Chromium Vi ◽  
Leaf Powder ◽  
Significant Achievement

Biosorption of chromium (Cr(VI)) is studied by using raw (chemically not modified) Moringa (Moringa Oleifera) leaf powder without any pretreatment. Cr(VI) is one of the potentially harmful heavy metals found in industrial wastewater. In the Moringa leaf powder, the presence of a significant amount of organic acids form the source for the biosorption of Cr(VI). The concentration of Cr(VI) in the feed solution is varied and different dosages of the proposed biosorbent are used to study its efficiency in the removal of Cr(VI). The concentration of Cr(VI) is varied from 1 ppm to 20 ppm while the amount of biosorbent is varied from 0.5 g to 2.5 g. The equilibrium time for adsorption of Cr(VI) is observed to vary between half an hour and 90 min. The metal removal efficiency varied from 30% to 90% which is a significant achievement compared to other conventional methods which are either energy-intensive or not cost effective. The experimental results are modeled using Langmuir, Freundlich and Redlich–Peterson isotherms. The metal removal efficiency is attributed to the chelating effect of carboxylate and hydroxyl groups present in the moringa leaves and is confirmed from the FTIR analysis. Further molecular docking simulations are performed to confirm the binding of the metal to the speculated sites within the different acids present in the moringa leaves. Untreated green moringa leaf powder used as a biosorbent in this study leads to a sustainable and cheaper option for treating wastewater containing Cr(VI).

scholarly journals Removal Efficiency of Acid Red 18 Dye from Aqueous Solution Using Different Aluminium-Based Electrode Materials by Electrocoagulation Process

2020 ◽  
Vol 20 (3) ◽  
pp. 536
Author(s):  
Nurulhuda Amri ◽  
Ahmad Zuhairi Abdullah ◽  
Suzylawati Ismail
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Industrial Wastewater ◽  
Electrode Materials ◽  
Cost Effective ◽  
Aluminium Electrode ◽  
Electrocoagulation Process ◽  
Commercial Aluminium ◽  
A Current ◽  
Better Than

This work compares commercial aluminium electrode for use in the treatment of wastewater by electrocoagulation process against waste aluminium cans electrode. The applicability of the waste aluminium cans electrode was tested for decolorization of Acid Red 18 dye as a model pollutant. The batch electrocoagulation process using both types of electrode was conducted at a current density of 25 mA/cm2, a pH of 3, an initial concentration of 100 mg/L and 25 min of reaction time. The elemental composition and surface morphology of both electrode materials and the sludge produced were analyzed using SEM-EDX to establish the correlation between the properties and characteristics of both electrode materials with their dye removal performance. The results demonstrated that waste aluminium cans performed better than commercial aluminium electrode with a removal efficiency of 100% in 25 min of reaction time. This was due to the higher Al dissolution of waste aluminium cans electrode that contributed to the larger amount of Al3+ released into the solution to consequently form more flocs to remove the dye molecules. In conclusion, the proposed waste aluminium electrode was considered as efficient and cost-effective and had the potential to replace the conventional ones in treating colored industrial wastewater using electrocoagulation process.

scholarly journals Chromium removal from tannery effluents by adsorption process via activated carbon chat stems (Catha edulis) using response surface methodology

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yigezu Mekonnen Bayisa ◽  
Tafere Aga Bullo ◽  
Desalegn Abdissa Akuma
Keyword(s):  
Heavy Metals ◽  
Activated Carbon ◽  
Removal Efficiency ◽  
Cost Effective ◽  
Treatment Method ◽  
Proximate Analysis ◽  
Chromium Removal ◽  
Tannery Effluents ◽  
Chromium Vi ◽  
Before And After

Abstract Objective In tannery processing, water consumption is high, which generates wastewater as a by-product and numerous pollutants such as chromium heavy metals that make adverse effects of water bodies and the surrounding environment. This study analyzed, chromium (VI) removal from wastewater through activated carbon chat stem was investigated. Adsorption is a common treatment method via activated carbon due to its cost-effective, profitable, and removal efficiency of these heavy metals. Results The proximate analysis of moisture content of chat stem has 6%, activated carbon ash content of 17.35%, volatile materials of 20.12%, and fixed carbon contents of 56.53%, which are well-matched the standards quality of activated carbon. As the process parameter varies, the increment of the chromium removal efficiency was from 62.5 to 97.03%. The maximum adsorption efficiency was observed at 30 g/L dosage of the adsorbent, at pH 4, and contact time at 180 min of activated carbon from chat stem waste was found 97.03%. FTIR was used to characterize the surface of the chat stem before and after adsorption. Langmuir and Freundlich are used for short contact time’s adsorption isotherm 0.9839 and 0.9995 respectively, which conformed, no visible change in the corrosion state.

scholarly journals Removal of chromium (VI) in aqueous solution by oat biomass (Avena sativa)

2017 ◽  
Vol 2 (2) ◽  
pp. 196-205
Author(s):  
Nancy Cecilia Pacheco-Castillo ◽  
Juan Fernando Cárdenas-González ◽  
María de Guadalupe Moctezuma Zarate ◽  
Víctor Manuel Martínez-Juárez ◽  
Adriana Rodríguez-Pérez ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Avena Sativa ◽  
Industrial Wastewater ◽  
Metal Removal ◽  
Effect Of Temperature ◽  
Ph Values ◽  
Chromium Vi ◽  
Removal Capacity ◽  
Oat Biomass

Chromium (VI) removal capacity in aqueous solution by oat biomass was analyzed by the diphenylcarbazide method. Bioadsorption was evaluated at different pH values (1, 2, 3 and 4) and at different times. The effect of temperature in the range of 28 °C to 60 °C and the removal at different initial Cr (VI) concentrations of 200 to 1000 mg/L were also studied. The highest bioadsorption (100% with 100 mg/L of the metal and 1 g of biomass) was at 8 h, at pH of 1.0 and 28 °C. With regard to temperature, the highest removal was to 60 oC, with a 100% removal at 90 min. Removal was more efficient when higher concentrations of biomass were used (100%, 3 h and 5 g of biomass). Untreated biomass (washed and ground biomass) showed excellent metal removal capacity in situ, 82.6% and 85.3% removal in contaminated soil and water, respectively, after 10 days of incubation, using 25 g of the biomass (100 mL of water). These results show that Cr (VI) can be removed from industrial wastewater using oat biomass.

Uncertainty in air stripping tower design: implications of the air-to-water ratio

2001 ◽  
Vol 1 (4) ◽  
pp. 177-184
Author(s):  
B.I. Dvorak ◽  
J.W. Schauble
Keyword(s):  
Mass Transfer ◽  
Removal Efficiency ◽  
Cost Effective ◽  
Air Stripping ◽  
Henry's Constant ◽  
True Value ◽  
Risk Of Failure ◽  
Process Failure ◽  
Removal Efficiencies ◽  
Water Ratio

Environmental engineers are frequently faced with uncertainty in making design decisions because the true value of many process parameters is unknown. In this study, the design of countercurrent air stripping towers was modeled using fuzzy numbers, taking into account uncertainties in mass transfer and Henry's constant. It was found that, in addition to cost, the risk of failure is an important design consideration for stripping tower design. A significant over-design is both cost-effective and results in less risk of design failure. The air-to-water ratio that yielded the least risk of failure switched from low to high as the removal efficiency of the tower increased. An important result is that at lower removal efficiencies, tower design and operation is most sensitive to uncertainties in mass transfer and at higher removal efficiencies, tower design and operation is most sensitive to uncertainties in Henry's constant . The implication is that low air-to-water ratios are best when the regulatory target removal efficiency is low and/or when the uncertainty in the value of the contaminant's Henry's constant is larger than the uncertainty in the mass transfer coefficient value. Otherwise a high air-to-water ratio results in the least risk of process failure.

scholarly journals Modification of cotton fabrics with 2-diethylaminoethyl chloride for salt-free dyeing with anionic dyes

Cellulose ◽  
2021 ◽  
Author(s):  
Peixin Tang ◽  
Leilah-Marie E. Lockett ◽  
Mengxiao Zhang ◽  
Gang Sun
Keyword(s):  
Electrostatic Interactions ◽  
Light Exposure ◽  
Dye Adsorption ◽  
Cost Effective ◽  
Cotton Fabrics ◽  
Cotton Cellulose ◽  
Hydroxyl Groups ◽  
Anionic Dyes ◽  
Free System ◽  
Untreated Cotton

AbstractA chemical modification of cotton fabrics by 2-diethylaminoethyl chloride (DEAE-Cl) was achieved, and the resulted cotton fabrics demonstrated salt-free dyeing properties with anionic dyes. Nucleophilic property of hydroxyl groups in cotton cellulose was enhanced under alkaline conditions and could react with DEAE-Cl, a chemical possessing both nucleophilic and electrophilic sites. The monolayered DEAE-grafted cotton cellulose could further react with DEAE-Cl to form multiple cationic quaternary ammonium salts (denoted as DEAE@Cotton), which are highly interactive with anionic dye molecules. The strong electrostatic interactions between the DEAE@Cotton and the dyes eliminated the use of inorganic salts in cotton dyeing process. The chemical structure and property of DEAE@Cotton were characterized and compared with untreated cotton. The DEAE@Cotton can be dyed in a salt-free system, and the dye exhaustion was faster than the conventional dyeing method due to the robust electrostatic interactions of the fabrics with anionic dyes. The dyed fabrics demonstrated outstanding color fastness under repeated washing, light exposure, and crocking. The dye adsorption process on DEAE@Cotton follows Langmuir isotherm model (R2 = 0.9667). The mechanism of enhanced dyeability was experimentally proved by treating the fabric with other anionic dyes in a salt-free system, proving the process to be environmentally friendly and cost-effective. Graphic abstract

Electrokinetic Remediation of Heavy Metal Contaminated Soil Using Permeable Reactive Composite Electrodes

2012 ◽  
Vol 518-523 ◽  
pp. 361-368 ◽  
Author(s):  
Rong Bing Fu ◽  
Xin Xing Liu ◽  
Fang Liu ◽  
Jin Ma ◽  
Yu Mei Ma ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Removal Efficiency ◽  
Heavy Metal Ions ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Ph Control ◽  
Electrokinetic Remediation ◽  
Composite Electrodes ◽  
Remediation Process

A new permeable reactive composite electrode (PRCE) attached with a permeable reactive layer (PRL) of Fe0 and zeolite has been developed for soil pH control and the improved removal efficiency of heavy metal ions (Cd, Ni, Pb, Cu) from soil in electrokinetic remediation process. The effects of different composite electrodes on pH control and heavy metal removal efficiency were studied, and changes in the forms of heavy metals moved onto the electrodes were analyzed. The results showed that with acidic/alkaline zeolite added and renewed in time, the composite electrodes could effectively neutralize and capture H+ and OH- produced from electrolysis of the anolyte and catholyte, avoiding or delaying the formation of acidic/alkaline front in tested soil, preventing premature precipitation of heavy metal ions and over-acidification of soil, and thus significantly improved the heavy metal removal efficiency. Fe0 in composite electrodes could deoxidize and stabilize the heavy metal ions. After that capture and immobilization of the pollutants were achieved. The results also showed that, using "Fe0 + zeolite" PRCE in the cathode with timely renewal, after 15-day remediation with a DC voltage of 1.5 V/cm, the total removal rates of Cd, Pb, Cu and Ni were 49.4%, 47.1%, 36.7% and 39.2%, respectively.

scholarly journals Exploiting the Potential in Water Cleanup from Metals and Nutrients of Desmodesmus sp. and Ampelodesmos mauritanicus

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1461
Author(s):  
Roberto Braglia ◽  
Lorenza Rugnini ◽  
Sara Malizia ◽  
Francesco Scuderi ◽  
Enrico Luigi Redi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Metal Removal ◽  
Anthropogenic Activities ◽  
Cost Effective ◽  
Single Species ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Sequential Approach ◽  
Removal Capacity ◽  
Green Microalga

Increasing levels of freshwater contaminants, mainly due to anthropogenic activities, have resulted in a great deal of interest in finding new eco-friendly, cost-effective and efficient methods for remediating polluted waters. The aim of this work was to assess the feasibility of using a green microalga Desmodesmus sp., a cyanobacterium Nostoc sp. and a hemicryptophyte Ampelodesmos mauritanicus to bioremediate a water polluted with an excess of nutrients (nitrogen and phosphorus) and heavy metals (copper and nickel). We immediately determined that Nostoc sp. was sensitive to metal toxicity, and thus Desmodesmus sp. was chosen for sequential tests with A. mauritanicus. First, A. mauritanicus plants were grown in the ‘polluted’ culture medium for seven days and were, then, substituted by Desmodesmus sp. for a further seven days (14 days in total). Heavy metals were shown to negatively affect both the growth rates and nutrient removal capacity. The sequential approach resulted in high metal removal rates in the single metal solutions up to 74% for Cu and 85% for Ni, while, in the bi-metal solutions, the removal rates were lower and showed a bias for Cu uptake. Single species controls showed better outcomes; however, further studies are necessary to investigate the behavior of new species.

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