scholarly journals Phytoremediation of some heavy metals in contaminated soil

Author(s):  
Sherine M. Shehata ◽  
Reham K. Badawy ◽  
Yasmin I. E. Aboulsoud

Abstract Background Several cultivated areas are irrigated with low-quality waters from the drainage system due to the shortage of suitable source of water for agricultural activities. Most of these drainage waters are contaminated with heavy metals which are concentrated in surface layer of the soil and translocated to plant and food chains. The region of Sahl El Husseiniya, Alsharqia government, is mainly irrigated with wastewater of Bahr El-Baqar drain. Objective Two types of hyperaccumulator plants represented by kenaf (Hibiscus cannabinus L.) and flax (Linum usitatissimum L.) were cultivated successively in the study area. Humic acid and gibberellin were used in this experiment as foliar sprayings to enhance the plant ability to absorb heavy metal ions from the soil. In addition, three soil additives represented by sulfur, vermiculite, and compost were also applied. Results Sulfur was the soil additive of the most pronounced effect on the uptake of Cr, Co, Cd, and Mn by the hyperaccumulator plants, while humic acid was of more favorable effect as a foliar treatment on Co and Cr uptake by flax and Cd and Mn uptake by kenaf. However, the foliar application of gibberellin enhanced plant growth and was of the best effect on both Co and Cr uptake by kenaf-cultivated soils and both Cd and Mn in flax-cultivated soils. In general, heavy metals were more concentrated in roots than in shoots. Comparing the efficiency of the two crops in cleaning soils, results implied that kenaf was of more favorable effect on the removal of Cr, Co, and Cd, while flax was of higher superiority in the removal of Mn. The efficiency of kenaf on removal of the studied metal ions followed the descending order of Cr > Co > Mn > Cd where their removal percentage values reached 50.71, 38.27, 33.98, and 14.43%, respectively. Flax phytoremediation efficiency followed the descending order of Mn > Cr > Co > Cd, where their removal percentage values reached 54.36, 36.95, 28.72, and 11.37%, respectively. Double season phytoremediation efficiency followed the order of Cr ≥ Mn > Co > Cd achieving 66.87, 65.63, 54.66, and 23.40%, respectively.

2013 ◽  
Vol 67 (5) ◽  
pp. 773-779 ◽  
Author(s):  
Ivana Kostic ◽  
Tatjana Andjelkovic ◽  
Ruzica Nikolic ◽  
Tatjana Cvetkovic ◽  
Dusica Pavlovic ◽  
...  

The complexation of humic acid with certain heavy metal ions (Co(II), Ni(II), Cu(II), Zn(II) and Pb(II)) was investigated. The stability constants of humate complexes were determined by method which is based on distribution of metal ions between solution and resin in the presence and the absence of ligand, known as Schubert?s ion exchange method. Experiments were performed at 25 ?C, at pH 4.0 and ionic strength of 0.01 mol dm-3. It was found that the 1:1 complexes were formed between metal ions and humic acid. Obtained results of the stability constants, log ?mn, of complexes formed between the metal ions and humic acid follow the order Co(II) < Ni(II) < Cu(II) > Zn(II) which is the same like in the Irving-Williams series for the binding strength of divalent metal ion complexes. Stability constant of complex between Pb(II) ions and humic acid is greater than stability constants of other investigated metal-humate complexes. The investigation of interaction between heavy metal ions and humics is important for the prediction of the distribution and control of the migration of heavy metals in natural environment.


2012 ◽  
Vol 550-553 ◽  
pp. 2428-2435
Author(s):  
Fang Yan Chen ◽  
Wei Ye ◽  
Yu Bin Tang

A novel organic-inorganic composite sodium polyacrylate-humic acid-rectorite was prepared by polymerization reaction of acrylic acid, humic acid and rectorite in aqueous solution and used as adsorbent for removal of heavy metals Pb(II), Cd(II), Cu(II) and Zn(II) ions from aqueous solution. The effects of contact time, pH, temperature and adsorbent dosage on adsorption capability were investigated. Adsorption kinetics, adsorption isotherm and desorption of adsorbed heavy metal ions were also researched. The results indicated that the adsorption reaction of heavy metals was rapid and reached equilibrium in 30 min. Adsorption capacities of heavy metals increased with increasing initial pH, temperature and adsorbent dosage. Adsorption reaction is endothermic. The optimum pH for all the four ions adsorption was observed at 5.5-6.5. The removal rate of Pb(II), Cd(II), Cu(II) ions with initial concentration of 50mg/L are more than 98%, and Zn(II) ions removal is about 90%. The suitability of adsorption kinetics for heavy metals to a pseudo-second-order kinetics model suggested that the adsorption rate may be governed by chemiadsorption involving ions exchange or sharing between adsorbent and metal ions. The adsorption equilibrium data was well interpreted by Langmuir and Freundlich isotherm model. The adsorption behaved as monomolecular layer. The maximum monolayer adsorption capacity was 1666.7, 666.7, 303.0 and 454.6 mg∙g-1 for Pb(II), Cd(II), Cu(II) and Zn(II) ions, respectively, at 25°C. Adsorbed metal ions were desorbed effectively by 0.1M HCl solution. Desorption rate was about 95.2, 92.4, 98.7 and 94.3% for Pb(II), Cd(II), Cu(II) and Zn(II) ions, respectively. Adsorbent can be reused for three cycles without any significant loss in adsorption performance.


SoilREns ◽  
2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Firda Firda ◽  
Oviyanti Mulyani ◽  
Anni Yuniarti

Soil is a very complex and dynamic system, consisting of the solid, liquid and gas. The solid parts of soil is made from minerals and organic materials (rough and smooth). Organic materials with smooth from is called humic acid. This product is a result from oxidation polimeritation of compounds like phenol, lignin and proteins from plants also from the metabolism of microorganism in the ground. In general, the composition of organic matter is dominated by humin with large, medium and lower of molecular weight. Humic acid has the composition of elements like carbon (40-80%), nitrogen (2-4%), sulfur (1-2%), phospor (0-0,3%) and also oxygen. Humic acid has unique characteristics compared with fulvic acid and humin. One of the most spesific character is the bonding to interact with metal ions, oxide, hydroxide, minerals, organic, and toxic materials.Key words: Adsorbtion, Characterization, Heavy metals, Humic Acid


2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Esmat Ahmed Abou El-Anwar

Abstract Background Aswan and Luxor Governorates are characterized by multifaceted activities such as cement, chemicals, fertilizers, detergents, nitrogen fertilizer factory at Aswan, the sugar and diary factory at Kom Ombo, and several other factories such as the sugar, pulp, paper, ferrosilicon, and phosphate factories at Edfu, urbanization and agriculture. In addition, there is a main sewage station which is used for irrigation of many crops. Assessing the pollution of soil and sediment with some heavy metals in these areas is the main aim of the current work. Results The average heavy metals content in the studied cultivated soils and Nile sediments are above the acceptable levels. Generally, Nile sediments and cultivated soils at Aswan and Luxor were unpolluted to moderately polluted with heavy metals. Pollution indices indicated that the studied Nile sediments were at considerably ecological risk from Cd (Er = 138.89) and Zn (Er = 140.52). In contrast, the cultivated soil was at very high ecological risk from Cd (Er = 295.24). Conclusions The current research revealed that the soil and sediments in the Upper Egypt are less polluted than Lower Egypt. Thus, the concentrations of toxic elements are increased from south to north direction in Egypt along the Nile River. The sources of the toxic metals may possibly be natural or anthropogenic in the studied area. The anthropogenic source is resulting from paper, pulp, ferrosilicon factories, and phosphate mining at Edfu. In addition, there are some polluting industries such as sand quarry, shale mining, and the nitrogen fertilizer factory at Aswan. On the other hand, the natural sources of toxic waste are the drains during the seasonal flash floods.


2021 ◽  
Vol 6 (1) ◽  
pp. 115-123
Author(s):  
Luísa P. Cruz-Lopes ◽  
Morgana Macena ◽  
Bruno Esteves ◽  
Raquel P. F. Guiné

Abstract Industrialization increases the number of heavy metals released into the environment. Lead (Pb2+), nickel (Ni2+) and chromium (Cr6+) are among these toxic metals and cause irreversible effects on ecosystems and human health due to their bio-accumulative potential. The decontamination through adsorption processes using lignocellulosic wastes from agricultural and/or forestry processes is a viable solution. Hence, this work aimed at studying the effect of pH on the biosorption of the metal ions using four different by-product materials: walnut shell, chestnut shell, pinewood and burnt pinewood. These experiments were conducted with solutions of the three heavy metals in which the adsorbents were immersed to measure the rate of adsorption. A range of pH values from 3.0 to 7.5 was used in the experiments, and the concentrations were determined by atomic absorption. The results showed different behaviour of the biosorbent materials when applied to the different metals. The lead adsorption had an ideal pH in the range of 5.5–7.5 when the walnut shell was used as an adsorbent, corresponding to values of adsorption greater than 90%, but for the other materials, maximum adsorption occurred for a pH of 7.5. For the adsorption of chromium, the pH was very heterogeneous with all adsorbents, with optimal values of pH varying from 3.0 (for chestnut shell) to 6.5 (for walnut shell and wood). For nickel, the best pH range was around pH 5, with different values according to the lignocellulosic material used. These results indicate that the tested biosorbents have the potential to decontaminate wastewater in variable extensions and that by controlling the pH of the solution; a more efficient removal of the heavy metals can be achieved.


2007 ◽  
Vol 544-545 ◽  
pp. 95-98 ◽  
Author(s):  
Jong Tae Jung ◽  
Jong Oh Kim ◽  
Won Youl Choi

The purpose of this study is to investigate the effect of the operational parameters of the UV intensity and TiO2 dosage for the removal of humic acid and heavy metals. It also evaluated the applicability of hollow fiber microfiltration for the separation of TiO2 particles in photocatalytic microfiltration systems. TiO2 powder P-25 Degussa and hollow fiber microfiltration with a 0.4 μm nominal pore size were used for experiments. Under the conditions of pH 7 and a TiO2 dosage 0.3 g/L, the reaction rate constant (k) for humic acid and heavy metals increased with an increase of the UV intensity in each process. For the UV/TiO2/MF process, the reaction rate constant (k) for humic acid and Cu, with the exception of Cr in a low range of UV intensity, was higher compared to that of UV/TiO2 due to the adsorption of the membrane surface. The reaction rate constant (k) increased as the TiO2 dosage increased in the range of 0.1~0.3 g/L. However it decreased for a concentration over 0.3 g/L of TiO2. For the UV/TiO2/MF process, TiO2 particles could be effectively separated from treated water via membrane rejection. The average removal efficiency for humic acid and heavy metals during the operational time was over 90 %. Therefore, photocatalysis with a membrane is believed to be a viable process for humic acid and heavy metals removal.


2013 ◽  
Vol 789 ◽  
pp. 176-179 ◽  
Author(s):  
Eny Kusrini ◽  
Nofrijon Sofyan ◽  
Dwi Marta Nurjaya ◽  
Santoso Santoso ◽  
Dewi Tristantini

Hydroxyapatite/chitosan (HApC) composite has been prepared by precipitation method and used for removal of heavy metals (Cr6+, Zn2+and Cd2+) from aqueous solution. The HAp and 3H7C composite with HAp:chitosan ratio of 3:7 (wt%) were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy-energy dispersive X-ray spectroscopy. The SEM results showed that HAp is spherical-shaped and crystalline, while chitosan has a flat structure. SEM micrograph of 3H7C composite reveals crystalline of HAp uniformly spread over the surface of chitosan. The crystal structure of HAp is maintained in 3H7C composite. Chitosan affects the adsorption capacity of HAp for heavy metal ions; it binds the metal ions as well as HAp. The kinetic data was best described by the pseudo-second order. Surface adsorption and intraparticle diffusion take place in the mechanism of adsorption process. The binding of HAp powder with chitosan made the capability of composite to removal of Cr6+, Zn2+and Cd2+from aqueous solution effective. The order of removal efficiency (Cr6+> Cd2+> Zn2+) was observed.


Author(s):  
Simranjeet Singh ◽  
Vijay Kumar ◽  
Amith G. Anil ◽  
Romina Romero ◽  
Praveen C. Ramamurthy ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mulu Berhe Desta

Adsorption of heavy metals (Cr, Cd, Pb, Ni, and Cu) onto Activated Teff Straw (ATS) has been studied using batch-adsorption techniques. This study was carried out to examine the adsorption capacity of the low-cost adsorbent ATS for the removal of heavy metals from textile effluents. The influence of contact time, pH, Temperature, and adsorbent dose on the adsorption process was also studied. Results revealed that adsorption rate initially increased rapidly, and the optimal removal efficiency was reached within about 1 hour. Further increase in contact time did not show significant change in equilibrium concentration; that is, the adsorption phase reached equilibrium. The adsorption isotherms could be fitted well by the Langmuir model. The value in the present investigation was less than one, indicating that the adsorption of the metal ion onto ATS is favorable. After treatment with ATS the levels of heavy metals were observed to decrease by 88% (Ni), 82.9% (Cd), 81.5% (Cu), 74.5% (Cr), and 68.9% (Pb). Results indicate that the freely abundant, locally available, low-cost adsorbent, Teff straw can be treated as economically viable for the removal of metal ions from textile effluents.


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