scholarly journals Evaluation of Groundwater and Grey Water Contamination with Heavy Metals and Their Adsorptive Remediation Using Renewable Carbon from a Mixed-Waste Source

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1802
Author(s):  
Taghrid S. Alomar ◽  
Mohamed A. Habila ◽  
Zeid A. Alothman ◽  
Najla AlMasoud ◽  
Saad Saeed Alqahtany

The contamination of water sources with heavy metals is a serious challenge that humanity is facing worldwide. The aim of this work was to evaluate and remediate the metal pollution in groundwater and greywater resources from Riyadh, Saudi Arabia. In addition, we investigated the application of ultrasonic power before adsorption to assess the dispersion of renewable carbon from mixed-waste sources (RC-MWS) as an adsorbent and enhance the water purification process. The renewable carbon adsorbent showed high ability to adsorb Pb(II), Zn(II), Cu(II), and Fe(II) from samples of the actual water under study. The conditions for the remediation of water polluted with heavy metals by adsorptive-separation were investigated, including the pH of the adsorption solution, the concentration of the heavy metal(s) under study, and the competition at the adsorption sites. The enhanced adsorption process exhibited the best performance at a pH of 6 and room temperature, and with a contact time of 60 min. Kinetic studies showed that the pseudo-second-order kinetic model was fitted with the adsorption of Pb(II), Zn(II), Cu(II), and Fe(II) onto the RC-MWS. The adsorption data were well fitted by Langmuir isotherms. The Freundlich isotherm was slightly fitted in the cases of Cu(II), Zn(II), and Fe(II), but not in the cases of Pb(II). The developed adsorption process was successfully applied to actual water samples, including water samples from Deria and Mozahemia and samples from clothes and car washing centers in Riyadh city.

Author(s):  
Jurgita Seniūnaitė ◽  
Rasa Vaiškūnaitė ◽  
Kristina Bazienė

Research studies on the adsorption kinetics are conducted in order to determine the absorption time of heavy metals on coffee grounds from liquid. The models of adsorption kinetics and adsorption diffusion are based on mathe-matical models (Cho et al. 2005). The adsorption kinetics can provide information on the mechanisms occurring be-tween adsorbates and adsorbents and give an understanding of the adsorption process. In the mathematical modelling of processes, Lagergren’s pseudo-first- and pseudo-second-order kinetics and the intra-particle diffusion models are usually applied. The mathematical modelling has shown that the kinetics of the adsorption process of heavy metals (copper (Cu) and lead (Pb)) is more appropriately described by the Lagergren’s pseudo-second-order kinetic model. The kinetic constants (k2Cu = 0.117; k2Pb = 0,037 min−1) and the sorption process speed (k2qeCu = 0.0058–0.4975; k2qePb = 0.021–0.1661 mg/g per min) were calculated. After completing the mathematical modelling it was calculated that the Langmuir isotherm better reflects the sorption processes of copper (Cu) (R2 = 0.950), whilst the Freundlich isotherm – the sorption processes of lead (Pb) (R2 = 0.925). The difference between the mathematically modelled and experimen-tally obtained sorption capacities for removal of heavy metals on coffee grounds from aqueous solutions is 0.059–0.164 mg/l for copper and 0.004–0.285 mg/l for lead. Residual concentrations of metals in a solution showed difference of 1.01 and 0.96 mg/l, respectively.


2010 ◽  
Vol 113-116 ◽  
pp. 632-638
Author(s):  
Feng Yu Li ◽  
Xiao Mei Sun ◽  
Bu Hai Li

Batch adsorption experiments were carried out to remove heavy metals Cu(II)and Ni(II) by pyromellitic dianhydride (PMDA) grafted β-Cyclodextrin (β-CD). The effects concerning the pH of the solution, contact time and initial heavy metal concentration were studied and discussed. The adsorption values increased significantly after a large number of carboxyl groups were gragfted on the microspheres surface. In order to investigate the mechanism of sorption, adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetic equation. It was found that kinetic studies showed good correlation coefficients for a pseudo-second-order kinetic model, confirming that the sorption rate was controlled by chemical adsorption. The equilibrium process was better described by the Langmuir isotherm than the Freundlich isotherm. XPS analysis further confirmed that the carboxyl group which grafted on the surface of the β-CD microspheres play a very important role in the removal of heavy metals.


2020 ◽  
Author(s):  
Bernice Y. Danu ◽  
Eric S. Agorku ◽  
Francis K. Ampong ◽  
Johannes A.M. Awudza ◽  
Vincent Torve ◽  
...  

Abstract A novel bio-nanocomposite, FeS encapsulated chitosan grafted polyacrylamide, was successfully synthesized using a grafting technique that employs microwave irradiation. Employing FTIR, SEM, XRD, TEM and SAED analysis, the synthesized nanocomposites were characterized. Thermodynamic and kinetic studies were accomplished using the batch mode via the eosin yellow adsorption from aqueous solution using the nanocomposite. The adsorption process was tailored to the pseudo-second-order kinetic model and the Freundlich isotherm model. The enthalpy change, ∆H° (-12.243 kJ/mol), was an exothermic process. The Gibbs energy, ∆G° (from -5.492 kJ/mol.K to -5.078 kJ/mol.K for temperatures from 300 K to 318 K respectively) values were indications of a thermodynamically feasible reaction process which was spontaneous within the temperature domain. The change in entropy, ∆S° (-0.023 kJ/mol), showed reduced randomness during the adsorption process. The mean free energy of adsorption was 0.408 kJ/mol, which was an indication of physisorption. These results show the possible use of the graft copolymer as an adsorbent in water treatment.


Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  

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.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4318
Author(s):  
Elie Meez ◽  
Abbas Rahdar ◽  
George Z. Kyzas

The threat of the accumulation of heavy metals in wastewater is increasing, due to their abilities to inflict damage to human health, especially in the past decade. The world’s environmental agencies are trying to issue several regulations that allow the management and control of random disposals of heavy metals. Scientific studies have heavily focused on finding suitable materials and techniques for the purification of wastewaters, but most solutions have been rejected due to cost-related issues. Several potential materials for this objective have been found and have been compared to determine the most suitable material for the purification process. Sawdust, among all the materials investigated, shows high potential and very promising results. Sawdust has been shown to have a good structure suitable for water purification processes. Parameters affecting the adsorption mechanism of heavy metals into sawdust have been studied and it has been shown that pH, contact time and several other parameters could play a major role in improving the adsorption process. The adsorption was found to follow the Langmuir or Freundlich isotherm and a pseudo second-order kinetic model, meaning that the type of adsorption was a chemisorption. Sawdust has major advantages to be considered and is one of the most promising materials to solve the wastewater problem.


Author(s):  
Tasrina R. Choudhury ◽  
Snahasish Bhowmik ◽  
M. S. Rahman ◽  
Mithun R. Nath ◽  
F. N. Jahan ◽  
...  

Sawdust supported nano-zerovalent (NZVI/SD) iron was synthesized by treating sawdust with ferrous sulphate followed by reduction with NaBH4. The NZVI/SD was characterized by SEM, XRD, FTIR and Chemical method. Adsorption of As (III) by NZVI/SD was investigated and the maximum uptake of As (III) was found at pH value of 7.74 and equilibrium time of 3 hrs. The adsorption isotherm modelling revealed that the equilibrium adsorption data were better fitted with the Langmuir isotherm model compared with the Freundlich Isotherm model. This study revealed that the maximum As (III) ions adsorption capacity was found to be 12.66 mg/g for using NZVI/SD adsorbent. However, the kinetics data were tested by pseudo-first-order and pseudo-second-order kinetic models; and it was observed that the adsorption data could be well fitted with pseudo-second-order kinetics for As (III) adsorption onto NZVI/SD depending on both adsorbate concentration and adsorption sites. The result of this study suggested that NZVI/SD could be developed as a prominent environment-friendly adsorbent for the removal of As (III) ions from aqueous systems.


2021 ◽  
Vol 348 ◽  
pp. 01016
Author(s):  
Rajaa Bassam ◽  
Marouane El Alouani ◽  
Nabila Jarmouni ◽  
Jabrane Maissara ◽  
Mohammed El Mahi Chbihi ◽  
...  

Heavy metals are the most dangerous inorganic pollutants Due to their bioaccumulation and their nonbiodegradability, for this, several studies have focused on the recovery of these metals from water using different techniques. In this context, our study consists of evaluating an efficient and eco-friendly pathway of competitive recovery of heavy metals (Cd, Cr and As) from aqueous solutions by adsorption using raw rock. This adsorbent was characterized before and after the adsorption process by several techniques. The multi-metals adsorption process in the batch mode was undertaken to evaluate the effect of adsorbent mass, contact time, pH, Temperature, and initial heavy metals concentration. The kinetic data were analyzed using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models. According to the modeling of the experimental results, the adsorption kinetics of heavy metals were adapted to the pseudo-second-order model. The adsorption isotherms were evaluated by the Langmuir and Freundlich isotherm models. The experimental isotherm data of heavy metals were better fitted with the Langmuir model rather than Freundlich isotherm models. The maximum experimental adsorption capacities (Qmax) predicted by the Langmuir model are 15.23 mg/g for Cd (II), 17.54 mg/g for Cr (VI) and 16.36 mg/g for As (III). The values of thermodynamic parameters revealed that the heavy metals adsorption was exothermic, favorable, and spontaneous in nature. The desorption process of heavy metals showed that this raw rock had excellent recycling capacity. Based on the results, these untreated clays can be used as inexpensive and environmentally friendly adsorbents to treat water contaminated by heavy metals.


2017 ◽  
Vol 2 (1) ◽  
pp. 13-26
Author(s):  
Tengku Khamanur Azma Tg. Mohd Zamri ◽  
Mimi Sakinah Abd Munaim ◽  
Zularisam Ab Wahid

Natural dye extracted from the rhizome of Curcuma longa L. were applied to bamboo yarns using exhaustion dyeing process. This study investigates the dyeing behaviour of Curcumin; the major color component isolated from rhizomes of Curcuma longa L.on bamboo yarn. Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich isotherm models were used to test the adsorption process of curcumin on bamboo yarn. Comparison of regression coefficient value indicated that the Freundlich isotherm most fitted to the adsorption of curcumin onto bamboo yarn. Furthermore, the kinetics study on this research fitted the pseudo-second order model which indicates that the basis of interaction was chemical adsorption.


2018 ◽  
Vol 78 (3) ◽  
pp. 476-486 ◽  
Author(s):  
Sergio I. Rojas ◽  
Diana C. Duarte ◽  
Sergio D. Mosquera ◽  
Felipe Salcedo ◽  
Juan P. Hinestroza ◽  
...  

Abstract We report on the role of ester bonds in the enhanced removal of hexavalent chromium from water using cotton fibers coated with chitosan. Adsorption capacities up to five times higher than those of the unmodified fibers were observed when the cotton fibers were exposed to an NaOH, followed by citric acid (0.97 M), and a chitosan solution (2%). We found that the use of NaOH favors the formation of ester bonds over amide bonds on the surface of the cotton fibers. This increase in the surface density of ester bonds generates an increase in the amount of exposed amino groups from the chitosan, hence increasing the removal capacity of the modified fibers. Experimental results also reveal that the adsorption is induced by the electrostatic attraction between the protonated amino groups on the surface and the negatively charged chromium ions in the water. Adsorption isotherms and kinetic studies indicated that the adsorption process fits the Langmuir and the Freundlich isotherm models as well as the pseudo-first and pseudo-second order kinetic models. These results can open a new avenue for the manufacturing of fibers with enhanced removal capacities for hexavalent chromium.


2017 ◽  
Vol 18 (4) ◽  
pp. 1406-1419
Author(s):  
F. Elmi ◽  
R. Chenarian Nakhaei ◽  
H. Alinezhad

Abstract This study is the first report of its type demonstrating the synthesis of mHAP on the basis of magnetic functionalization with nHAP, which were synthesized using Rutilus frisii kutum fish scale as a benign fishery waste by-product. The mHAP was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX), and Fourier transform infrared (FT-IR) spectroscopic techniques. The XRD pattern confirmed the formation of a single-phase nHAP without any extra steady phases. It was also found that the pseudo-second-order kinetic model gave a satisfactory fit to the experimental data (R2 = 0.99). The maximum removal percentages of Cu and Zn ions in optimal conditions (adsorbent dosage at 0.1 g, 30 min contact time at 25 ± 1 °C and pH = 5 ± 0.1) by mHAP were 97.1% and 93.8%, respectively. Results also demonstrated that mHAP could be recycled for up to five cycles in the case of copper and zinc. The Langmuir isotherm was proved to have a better correlation compared with that of the Freundlich isotherm. The thermodynamic parameters indicated that it was a spontaneously endothermic reaction. In conclusion, mHAP could be regarded as a powerful candidate for efficient biosorbent, capable of adsorbing heavy metals from aqueous solutions.


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