Species Distribution of Heavy Metals in Enhanced Electrokinetic Removal Process

2011 ◽  
Vol 71-78 ◽  
pp. 910-913
Author(s):  
Zhong Hui Xu ◽  
Dong Wei Li ◽  
Xi Peng

In this study, in order to evaluate the migration of heavy metals in enhanced electrokinetic removal,visual minteq was adopted to calculate the species distribution of heavy metals in different pH. Most of the heavy metals except arsenic generated the enrichment near the cathode area. Arsenate always existed as anion such as AsO43-、H2AsO4-、HAsO42-. Near the alkaline area ,the main form of heavy metals were alkali metal hydroxides and seriously restricted the migration and removal of heavy metals. The addition of potassium tetroxalate did not change the species distribution of heavy metals obviously.The nitric acid was more efficient than potassium tetroxalate to condition enhanced electrokinetic removal. Nevertheless ,both of two enhancement still need to be impoved to promote the removal efficiency.

2021 ◽  
Vol 900 (1) ◽  
pp. 012003
Author(s):  
M Balintova ◽  
Z Kovacova ◽  
S Demcak ◽  
Y Chernysh ◽  
N Junakova

Abstract Removal of heavy metals from the environment is important for living beings. The present work investigates the applicability of the natural and MnO2 - coated zeolite as sorbent for the removal of copper from synthetic solutions. Batch experiments were carried out to identify the influence of initial pH and concentration in the process of adsorption. A maximum removal efficiency of Cu(II) was observed in 10 mg/L for natural (95.6%) and modified (96.4%) zeolite, where the values was almost identical, but at concentration of 500 mg/L was the removal efficiency of modified zeolite three times higher. Based on the correlation factors R2, the Langmuir isotherms better describe the decontamination process than Freundlich. The optimum pH value was set at 5.0.


RSC Advances ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 1159-1167 ◽  
Author(s):  
X. F. Zhang ◽  
B. Wang ◽  
J. Yu ◽  
X. N. Wu ◽  
Y. H. Zang ◽  
...  

A porous carbon electrode with a 3D honeycomb-like structure demonstrates a high removal efficiency for the removal of chromium(vi) from water.


2020 ◽  
Vol 82 (10) ◽  
pp. 2148-2158
Author(s):  
K. H. Rekha ◽  
B. Lokeshappa

Abstract The study demonstrates the efficiency of the soil aquifer treatment (SAT) towards removal of heavy metals within electroplating wastewater thereby rendering it suitable for ground water discharge. The unique proposition of this research is to use a combination of soil and adsorbent properties to enhance the remediation of heavy metals such as nickel, copper and zinc. A comparative study through statistical analysis is employed to illustrate the effectiveness of the various SAT systems build using various combinations of SM and SC soil types along with bioadsorbents such as eucalyptus leaves, sawdust and Mosambi peel. Further, the mass balance analysis of heavy metals is carried out to comprehend the course of expulsion. The study, through a statistical approach, endorses that the SAT in conjunction with adsorbent gives much better removal efficiency than the SAT without adsorbent. Additional removal efficiency of 14% to 30% can be achieved with introduction of adsorbents within the SAT system. The optimal removal efficiency of nickel, copper and zinc was observed to be at 87, 98 and 93% respectively when passed through the combination of SM soil with sawdust.


Author(s):  
Ahmed M. AZZAM ◽  
Ahmed TAWFIK

Bio-flocculants produced by Bacillus sp. and Pseudomonas sp. were evaluated as flocculating agents for the removal of Cu (II), Pb (II) and Cd (II) from chemical and textile wastewater industries. Both bio-flocculants were very effective for removal of heavy metals at a dosage not exceeding 0.1 mg/ml. However, the removal efficiency of heavy metals was dependant on initial concentration and type of bio-flocculants. 84.0% of Cu2+ and 99.5% of Pb2+ were removed from industrial wastewater using Bacillus sp. Bio-flocculant resulting residual values of 28.5 and 1.13μg/l respectively in the treated effluent. Lower removal efficiencies of 70.4% for Cu2+ and 97.8% for Pb2+ occurred using Pseudomonas sp. bioflocculant. Nevertheless, Pseudomonas sp. bio-flocculant achieved a substantially higher removal efficiency of Cd2+ (93.5%) as compared to 72.9% using Bacillus sp. Based on these results bio-flocculants are considered as a viable alternative for the treatment of industrial wastewater containing heavy metals.


2021 ◽  
Vol 12 (5) ◽  
pp. 5941-5952

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).


2017 ◽  
Vol 8 (4) ◽  
pp. 235-239
Author(s):  
Hoang Phuong Thao Nguyen ◽  
Thi Hoang Ha Nguyen ◽  
Thi Kim Anh Bui

This study was carried out to evaluate the sorption capacity of Pb, As, Cd, Zn, and Mn by laterite from Tam Duong District (Vinh Phuc Province) and Thach That District (Hanoi City). Laterite sam- ples were exposed to different initial concentrations of heavy metals in solutions (2.5, 5.0, 10, 20, and 50 mg/l) at pH = 5.5 during 24 hours. The results demonstrated that sorption capacity of heavy metals was in the following order: Pb> As> Cd> Zn>Mn. The highest sorption capacity of Pb, As, Cd, Zn, and Mn of laterite from Tam Duong was 1553, 756, 397, 281, and 143 mg/kg, respectively and the highest removal efficiency was 94, 76, 70, 56 and 37%. The results indicated that laterite from Tam Duong District showed lower sorption capacity than that from Thach That District. The disparity sorption capacity of Pb, As, Cd, Zn, Mn between laterite from Thach That and Tam Duong was 10.3–11.6, 11.9–17.9, 11.5–13.7, 9.5–17.6, and 11.1–14.3%, respectively. Laterites from Tam Duong and Thach That are a promising environmental material which can be used in the removal of heavy metals from wastewater. Nghiên cứu này được thực hiện nhằm đánh giá khả năng hấp phụ Pb, As, Cd, Zn, và Mn bởi laterit đá ong khu vực huyện Tam Dương (Vĩnh Phúc) và huyện Thạch Thất (Hà Nội). Mẫu đá ong được tiến hành thí nghiệm trong các dung dịch có hàm lượng kim loại nặng ban đầu khác nhau (2,5; 5,0; 10; 20 và 50 mg/l) tại pH=5,5 trong 24 giờ. Kết quả nghiên cứu cho thấy mức độ hấp phụ kim loại nặng bởi laterit đá ong lần lượt là Pb> As> Cd> Zn>Mn. Dung lượng hấp phụ Pb, As, Cd, Zn và Mn cao nhất của laterit Tam Dương lần lượt là 1553, 756, 397, 281 và 143 mg/kg và hiệu suất hấp phụ cao nhất lần lượt là 94, 76, 70, 56 và 37%. Dung lượng hấp phụ kim loại nặng của laterit huyện Tam Dương thấp hơn khu vực huyện Thạch Thất. Sự chênh lệch về dung lượng hấp phụ Pb, As, Cd, Zn và Mn giữa laterit Thạch Thất và laterit Tam Dương lần lượt là 10,3–11,6; 11,9–17,9; 11,5– 13,7; 9,5–17,6 và 11,1–14,3%. Kết quả nghiên cứu bước đầu cho thấy đá ong khu vực huyện Tam Dương và Thạch Thất là vật liệu hấp phụ tiềm năng phục vụ ứng dụng trong xử lý nước thải bị nhiễm kim loại nặng.


2020 ◽  
Vol 980 ◽  
pp. 377-386
Author(s):  
Jing Liang Xie ◽  
Fei Fei Chi ◽  
Fan Li Meng ◽  
An Ran Peng

The removal of heavy metals in waste pickling acid by iron powder reduction was studied. The effects of reaction time, reaction temperature and dosage of iron powder on the removal efficiency of Zn, Cr, Ni and Pb in waste pickling acid were investigated. The results showed that, the removal rate of Cr tended to be stable after 2 h of reaction under magnetic stirring. After 4 hours, the removal rate of Zn,Ni and Pb tended to be stable. The temperature was increased from 20°C to 90 °C, the removal rates of Ni and Pb could be increased by 9.09% and 11.6%, while the removal rates of Zn and Cr were only increased by 1.15% and 2.85%; Increasing the dosage of iron powder was beneficial to the removal of heavy metals in waste pickling acid, and the combined amount of free acid in the waste acid would affect the removal efficiency of heavy metals. The research results had important guiding significance for the practical application of iron powder reduction method in the heavy metal purification project of waste pickling acid.


2019 ◽  
Vol 41 (2) ◽  
pp. 130-137
Author(s):  
Nguyen Thi Hoang Ha ◽  
Vu Thi Thom

Equisetum diffusum D. Don was transplanted into solutions added with different concentrations of Mn, Zn, Cd, Pb, and As for 30 days in the laboratory experiment to assess the removal of these metals and their accumulation in the plant. The highest removal efficiency of Mn, Zn, Cd, Pb, and As from solutions by E. diffusum was 99.6, 97.9, 77.5, 85.3, and 61.9%, respectively. The highest daily removal efficiencies of heavy metals were obtained after 1 day of new solution addition. The highest concentrations of Mn, Zn, Cd, Pb, and As in the plant roots were 7230, 1490, 174, 1170, and 274 mg/kg-DW, respectively; those in the shoots were 1960, 566, 33.9, 308, and 108 mg/kg-DW. The bioconcentration factor (BCF) values for Mn, Zn, Cd, Pb, and As were 496, 406, 702, 463, and 191, respectively. The results of this study indicate that E. diffusum has the ability to remove simultaneously these metals from water, making it a potential species for phytoremediation of water contaminated with multiple heavy metals.  


2021 ◽  
Vol 7 (1) ◽  
pp. 59-68
Author(s):  
Harsena Hayas Fika ◽  
Shinta Elystia ◽  
Aryo Sasmita

Soil contamination by heavy metals lead (Pb) and cadmium (Cd) is a form of pollution that is very dangerous for living things. One of the efforts to cultivate polluted soil is the remediation method using biochar from rice husks. The purpose of this study was to analyze the effect of biochar particle size variations on the removal of heavy metals Pb and Cd on contaminated soil. Biochar is made by pyrolysis at 500 0C for 1 hour and flows 0.1 L / minute of N2 gas. This study used a variety of biochar particle sizes of 100 mesh, 60 mesh, 40 mesh and testing time every 10 days for 1 month. The results of this study were the highest Pb and Cd removal in the addition of biochar with a particle size of 100 mesh, namely with a Pb concentration of 91.32 mg / kg and a removal efficiency of 54.05% ; Cd concentration of 10.47 mg / kg and a removal efficiency of 47.36%. Based on the results obtained, it can be stated that the smaller the biochar particle size, the efficiency of heavy metal removal will increase.


Author(s):  
O.Kameswara Rao ◽  
P. Venkateswarlu

The release of heavy metals into the environment is a worldwide major concern. Different studies have demonstrated that natural agents have a high removal capacity for divalent heavy metal ions. Wood ash is a natural adsorbent and, in comparison with others, has a very low price. In this study, the removal of heavy metals (Pb and Co) from Nippo Battery Industry (TADA, A.P.) effluent was investigated in batch condition. Pb and Co measurement in samples were done with atomic absorption equipment and test methods were adapted from standard methods for the examination of water and wastewater. The effect of pH and the amount of adsorbent was determined and different adsorption isotherms were also obtained. This study shows that the adsorption process follows the adsorption Langmuir isotherm. The amount of wood ash has a great role in the adsorption rate and adsorption rate increased as wood ash increased. In the study, the reactions reached equilibrium in 3 h contact time. The maximum Pb removal efficiency was 96.0% at pH 2 with a contact time of 3 h and 100 g/L wood ash and the maximum Co removal efficiency was 98.9 % at pH 2 with a contact time of 3 h and 100 g/L wood ash. According to the results, wood ash is recommended as a low cost and available adsorbent to remove Pb and Co from municipal and industrial wastewaters.


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