scholarly journals Integrated electrochemical-adsorption process for the removal of trace heavy metals from wastewater

Author(s):  
Ayesha Al Ali ◽  
Mariam Ouda ◽  
Vincenzo Naddeo ◽  
Sebastià Puig ◽  
Shadi W. Hasan
1999 ◽  
Vol 40 (7) ◽  
pp. 109-116 ◽  
Author(s):  
M. H. Ansari ◽  
A. M. Deshkar ◽  
P. S. Kelkar ◽  
D. M. Dharmadhikari ◽  
M. Z. Hasan ◽  
...  

Steamed Hoof Powder (SHP), size < 53μ, was observed to have high adsorption capacity for Hg(II) with >95% removal from a solution containing 100 mg/L of Hg(II) with only 0.1% (W/V) concentration of SHP. The SHP has good settling properties and gives clear and odour free effluent. Studies indicate that pH values between 2 and 10 have no effect on the adsorption of Hg(II) on SHP. Light metal ions like Na+, K+, Ca2+ and Mg2+ up to concentrations of 500 mg/L and heavy metals like Cu2+, Zn2+, Cd2+, Co2+, Pb2+, Ni2+, Mn2+, Cr3+, Cr6+, Fe2+ and Fe3+ up to concentrations of 100 mg/L do not interfere with the adsorption process. Anions like sulphate, acetate and phosphate up to concentrations of 200 mg/L do not interfere. Chloride interferes in the adsorption process when Hg(II) concentration is above 9.7 mg/L. The adsorption equilibrium was established within two hours. Studies indicate that adsorption occurs on the surface sites of the adsorbent.


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.


1978 ◽  
Vol 69 (3-4) ◽  
pp. 261-270 ◽  
Author(s):  
M. Dermelj ◽  
V. Ravnik ◽  
A. R. Byrne ◽  
A. Vakselj

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.


Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2659
Author(s):  
Muhammad Zaim Anaqi Zaimee ◽  
Mohd Sani Sarjadi ◽  
Md Lutfor Rahman

Natural occurrence and anthropogenic practices contribute to the release of pollutants, specifically heavy metals, in water over the years. Therefore, this leads to a demand of proper water treatment to minimize the harmful effects of the toxic heavy metals in water, so that a supply of clean water can be distributed into the environment or household. This review highlights several water treatment methods that can be used in removing heavy metal from water. Among various treatment methods, the adsorption process is considered as one of the highly effective treatments of heavy metals and the functionalization of adsorbents can fully enhance the adsorption process. Therefore, four classes of adsorbent sources are highlighted: polymeric, natural mineral, industrial by-product, and carbon nanomaterial adsorbent. The major purpose of this review is to gather up-to-date information on research and development on various adsorbents in the treatment of heavy metal from water by emphasizing the adsorption capability, effect of pH, isotherm and kinetic model, removal efficiency and the contact of time of every adsorbent.


Author(s):  
V. O. Wekpe ◽  
G. O. Chukwu-Okeah ◽  
Godspower Kinikanwo

City growth often time results in advancement and development in transportation which comes with its attendant changes in road infrastructure and transport support services such as road side mechanic workshops, vulcanizers and bus stops. A byproduct of these attendant contiguous activities and processes is the emission and release of trace heavy metals. Trace heavy metals have been identified as major carcinogens. This study aimed at determining the occurrence and concentration of heavy metals in roadside soils in an expanding third world metropolis. To achieve the aim of the research, the total length of the road within the study section was measured. Ten sample locations were indentified at about 2.5km intervals along the road section under review. The heavy metal concentration was determined the using Buck Scientific 210 VGP Atomic Absorption Spectrophotometer. Heavy metals such as Iron (Fe), Copper (Cu), Cadmium (Cd), Lead (Pb) and Mercury (Hg) were determined. The result of the analysis showed that the concentration values ranged from <0.001 to 48.90 µg/mg. The results also revealed that the experimental sample points recorded higher values than the control samples; however, some of the control points had relatively higher concentration values. This observation may have emanated from the low lying trajectory and topography of the surrounding area, which allows run-off from the road side soils to wash off heavy metals and deposit them at these lower lying areas. The sources of these trace heavy metals are attributed to emissions from motor vehicles that ply the road on a day to day basis. Emanating from the findings, this study recommends that improved public transportation and cleaner sources of energy is recommended.


2021 ◽  
Vol 1033 ◽  
pp. 82-86
Author(s):  
Tintin Mutiara ◽  
Andira Budi Trimartina ◽  
Rafika Erniza Putri ◽  
Achmad Chafidz

Industrial waste containing heavy metals can pollute the aquatic environment. One method that can be done to manage heavy waste is the adsorption method that uses adsorbent from cassava stem powder. This research was conducted to utilize cassava stem powder waste for the adsorption of Pb2 + metal ions. Cassava stem powder was mashed until it passed 100 mesh sieve. Cassava stems have a cellulose content of 70-80%, lignin 15-20%, ADF 15-20% and cellulose can be used as an absorber of heavy metals. The adsorption process is carried out with variations in pH, time and concentration under optimum conditions. In this adsorption involves the functional groups contained therein so that the interaction between the adsorbent with the metal ion Pb2 +. Based on the research, the optimum conditions were obtained at pH 6, 180 minutes contact time and 50 ppm concentration. This test is carried out using Atomic Absorption Spectroscopy (AAS).


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.


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