scholarly journals Disinfection of Raw Vegetable by Chemical Washing

2021 ◽  
Vol 38 (3) ◽  
pp. 107-117
Author(s):  
Yasuhiro Inatsu
Keyword(s):  
Chemical Washing

Assessment of ex-situ chemical washing of heavy metals from estuarine sediments around an industrial harbor in Southern Taiwan

2019 ◽  
Vol 19 (7) ◽  
pp. 3108-3122 ◽  
Author(s):  
Yu-Jen Shih ◽  
Syuan-Yao Syu ◽  
Chiu-Wen Chen ◽  
Chih-Feng Chen ◽  
Cheng-Di Dong
Keyword(s):  
Heavy Metals ◽  
Estuarine Sediments ◽  
Ex Situ ◽  
Chemical Washing ◽  
Southern Taiwan

Remediation of electronic waste polluted soil using a combination of persulfate oxidation and chemical washing

2017 ◽  
Vol 204 ◽  
pp. 170-178 ◽  
Author(s):  
Fu Chen ◽  
Zhanbin Luo ◽  
Gangjun Liu ◽  
Yongjun Yang ◽  
Shaoliang Zhang ◽  
...  
Keyword(s):  
Electronic Waste ◽  
Polluted Soil ◽  
Persulfate Oxidation ◽  
Chemical Washing

scholarly journals Changes in Soil Properties after Soil Washing of Metal-contaminated Soil near the former Janghang Smelter

2020 ◽  
Vol 42 (10) ◽  
pp. 482-492
Author(s):  
Keong-Hyeon An ◽  
Songhee Kim ◽  
Seung-Woo Jeong
Keyword(s):  
Soil Quality ◽  
Soil Texture ◽  
Contaminated Soil ◽  
Soil Property ◽  
Soil Health ◽  
Soil Washing ◽  
Fine Soil ◽  
Before And After ◽  
Chemical Washing ◽  
Changes In Soil Properties

Objectives : Changes in soil properties after washing of metal-contaminated soil near the former Janghang Smelter were investigated in this study. Contaminated input soils and remediated output soils were sampled from three different soil washing plants and analyzed for soil physical and chemical properties. Soil quality was evaluated by the soil fertilization guideline suggested by the Korea Rural Development Administration (KRDA). This study revealed the necessity of soil quality management for the remediated soil as an ecosystem member.Methods : Three soil washing plants (1OU, 2OU, 3OU) were commonly divided into the five steps: 1) the particle separation (crushing and grinding etc.) → 2) soil particle classification (big stone, fine soil, minimal fine soil) → 3) chemical washing (fine soil) → 4) neutralization of washed soil (lime) → 5) return-back to the original position. The separating minimum particle diameters of the 1OU, 2OU, and 3OU washing processes were 5 µm, 20 µm, and 10 µm, respectively, and the chemical washing solutions used were respectively 0.1 M H2SO4, 0.5 M H2SO4/0.5 M H3PO4, and 0.1 N NaOH-Na2CO3 (alkali reduction). Soils were collected before and after washing, air-dried, sieved with < 2 mm and analyzed for soil texture, bulk density, aggregate stability (AS), water holding capacity (WHC), pH, electrical conductivity (EC), organic matter content (OM), total nitrogen (TN), available phosphate (AvP), cation exchange capacity (CEC), exchangeable cations (potassium, calcium, magnesium, sodium).Results and Discussion : Sandy soil showed a big change in soil texture before and after soil washing, while there was no change in soil texture for fine soil. Sandy soil showed an increase in bulk density, a decrease in WHC, and a decrease in AS. The pH of remediated soil was affected by the type of washing chemical. The acidic washing processes (1OU, 2OU) resulted in low pH soils, while an alkali reduction process (3OU) showed high pH soil. The soil OM, TN, AvP and CEC decreased after soil washing. In the case of silty paddy soil, OM and TN were significantly reduced by washing. The most important change in soil property after washing was EC. After soil washing, the soil electrical conductivity increased sharply in all OUs : 1OU 0.51 → 6.21 ds/m, 2OU 1.09 → 3.73 ds/m, 3OU 0.99 → 9.30 ds/m. The EC values of the contaminated soil before washing were all less than 2 ds/m, which is an appropriate agricultural level. However, EC was significantly increased after washing, implying a strong salty soil level. The soil quality evaluation results before and after washing showed that the soil quality of heavy-metal contaminated soil was apparently degraded by washing. The number of soil property in the optimal range before washing (contaminated soil) was 10, but the number decreased to 5 after washing (remediated soil).Conclusions : Soil quality may be significantly changed after soil washing. The most noticeable change was the significant increase in the EC of soil and the soil health should be restored first to recycle the remediated soil. The important causes of changes in the soil quality were the separation of fine soil particles containing relatively high heavy metals from the bulk soil, soil disturbance by chemical washing solution and addition of high salts such as coagulants and pH adjust. Soil management schemes considering soil health should be soon prepared to restore the remediated soil back as an ecosystem member.

scholarly journals Effect of chelating agents on removal of 137Cs from contaminated soil

2018 ◽  
Vol 15 (35) ◽  
pp. 158-168
Author(s):  
Firas M. Radhi
Keyword(s):  
Removal Efficiency ◽  
Contaminated Soil ◽  
Chelating Agents ◽  
Soil Samples ◽  
Coarse Grained ◽  
Tetraacetic Acid ◽  
Mixing Ratio ◽  
Soil Mixing ◽  
Chemical Washing ◽  
Washing Method

In the present research, the chemical washing method has been selected using three chelating agents: citric acid, acetic acid and Ethylene Diamine Tetraacetic Acid (EDTA) to remove 137Cs from two different contaminated soil samples were classified as fine and coarse grained. The factors that affecting removal efficiency such as type of soil, mixing ratio and molarity have been investigated. The results revealed that no correlation relation was found between removal efficiency and the studied factors. The results also showed that conventional chemical washing method was not effective in removing 137Cs and that there are further studies still need to achieve this objective.

scholarly journals Defining the effect of the chemical concentration and solution pH on membrane chemical cleaning process

2019 ◽  
Vol 109 ◽  
pp. 00061
Author(s):  
Mykola Nechytailo ◽  
Olena Nahorna ◽  
Yevhenii Kosiuk
Keyword(s):  
Suspended Solids ◽  
Membrane Surface ◽  
Metal Salts ◽  
Chemical Concentration ◽  
Solution Ph ◽  
Chemical Cleaning ◽  
Negative Factor ◽  
Gel Layer ◽  
Chemical Washing ◽  
Active Substances

In the process of treating natural water from surface sources, precipitated substances are tend to be deposited on the ultrafiltration membrane, either as suspended solids or as gel structures, formed by humic substances with metal salts. Hydraulic washes are unable to remove gelled structures from the surface of the membranes. Consequently, the phenomenon of gelation on the surface of the membrane causes gradual decrease in productivity, which is a negative factor. Chemical washing of membranes is generally used to remove the gel layer from the membrane surface. In this paper, the range of compositions which effectively remove complex contaminants is proposed, and also the efficacy of both pH and changes in the concentration of active substances on the process of washing the membrane are analyzed.

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