Interactions BetweenEscherchia coliand the Colloids of Three Variable Charge Soils and Their Effects on Soil Surface Charge Properties

2014 ◽  
Vol 32 (6) ◽  
pp. 511-520 ◽  
Author(s):  
Zhao-Dong Liu ◽  
Zhi-Neng Hong ◽  
Jiu-Yu Li ◽  
Jun Jiang ◽  
Ren-Kou Xu
Keyword(s):  
Surface Charge ◽  
Soil Surface ◽  
Variable Charge ◽  
Variable Charge Soils

Effect of arsenate on adsorption of Zn(II) by three variable charge soils

Soil Research ◽  
2007 ◽  
Vol 45 (6) ◽  
pp. 465 ◽  
Author(s):  
Jing Liang ◽  
Ren-kou Xu ◽  
Diwakar Tiwari ◽  
An-zhen Zhao
Keyword(s):  
Zeta Potential ◽  
Surface Charge ◽  
Iron Oxides ◽  
Initial Concentration ◽  
Variable Charge ◽  
Study Results ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Enhanced Adsorption ◽  
Variable Charge Soils

The effect of arsenate on adsorption of Zn(II) in 3 variable charge soils (Hyper-Rhodic Ferralsol, Rhodic Ferralsol, and Haplic Acrisol) and the desorption of pre-adsorbed Zn(II) in the presence of arsenate were investigated in this study. Results showed that the presence of arsenate led to an increase in both the adsorption and desorption of Zn(II) in these variable charge soils. It was also suggested that the enhanced Zn(II) adsorption by arsenate was mainly due to the increase in negative surface charge of the soils induced by the specific adsorption of arsenate, and the increase in electrostatically adsorbed Zn(II) was responsible for the increase in the desorption of Zn(II). The effect of arsenate on Zn(II) adsorption primarily depends on the initial concentration of arsenate and Zn(II), the system pH, and the nature of soils. The enhanced adsorption of Zn(II) increased with the increase in the initial concentration of arsenate and the amount of arsenate adsorbed by the soils. The presence of arsenate decreased the zeta potential of soil suspensions and soil IEP and thus shifted the adsorption edge of Zn(II) to a lower pH region. The effect of arsenate on Zn(II) adsorption in these 3 soils followed the order Hyper-Rhodic Ferralsol > Rhodic Ferralsol > Haplic Acrisol, which was consistent to the contents of iron oxides in these soils and the amount of arsenate adsorbed by the soils.

Acidity

1997 ◽  
Author(s):  
X. L. Kong ◽  
X. N. Zhang
Keyword(s):  
Surface Charge ◽  
Soil Acidity ◽  
Solid Phase ◽  
Hydrogen Ions ◽  
Variable Charge ◽  
Aluminum Ions ◽  
Acid Reaction ◽  
The Relationship ◽  
Constant Charge ◽  
Variable Charge Soils

For variable charge soils, acidity is a property that is of equal importance as the surface charge. These two properties may affect each other, with the effect of the former on the latter more remarkable than the reverse. In the previous chapters it was shown that pH affects many other properties of the soil by affecting the surface charge. Therefore, soil acidity is more significant than surface charge in some aspects. Owing to a similar reason, the importance of acidity for variable charge soils may exceed that for constant charge soils. Soil acidity generally manifests itself in the form of hydrogen ions. Actually, these hydrogen ions are chiefly the product of the hydrolysis of aluminum ions. Therefore, when examining soil acidity it is necessary to examine the properties of aluminum ions. In the previous chapter the transformation of hydrogen ions into aluminum ions has already been mentioned. In this chapter the relationship between aluminum ions and hydrogen ions will be discussed in greater detail. Another difference between variable charge soils and constant charge soils with respect to acidity is that, not only hydrogen ions, but also hydroxyl ions can participate in chemical reactions between the solid phase and the liquid phase. In constant charge soils the quantity of hydroxyl ions is an induced variable and is determined by the quantity of hydrogen ions in the solution and the ionic product of water. In variable charge soils, on the other hand, the quantity is also determined by the chemical equilibrium of that ion species itself at the solid-solution interface. Thus, hydroxyl ions can, in turn, affect the quantity of hydrogen ions in solution. In this chapter the nature of acidity of variable charge soils will be discussed mainly from these characteristics. In the field of soil chemistry, there has been an interesting history with regard to the nature of soil acidity. Soon after the recognition of the relationship between acid reaction and hydrogen ions in chemistry, this concept of the nature of acidity was introduced into soil science, and the significance of hydrogen ions was invariably associated with it whenever soil acidity was considered.

Charge characteristics of soil in a lowland tropical moist forest in Panama in response to dry-season irrigation

Soil Research ◽  
2002 ◽  
Vol 40 (2) ◽  
pp. 269 ◽  
Author(s):  
Joseph B. Yavitt ◽  
S. Joseph Wright
Keyword(s):  
Surface Charge ◽  
Surface Soil ◽  
Soil Nutrient ◽  
Soil Surface ◽  
Nutrient Status ◽  
Dry Season ◽  
Soil Nutrient Status ◽  
Variable Charge ◽  
Subsurface Soil ◽  
Moist Forest

Although the hot, moist tropics in the Republic of Panama receive more than 2000 mm of rain per year, soils dry considerably during the 4-month dry season. We examined the effect of seasonal drought by irrigating two 2.25-ha plots of lowland tropical moist forest on Barro Colorado Island (BCI) for 5 consecutive dry seasons. Irrigation decreased soil permeability and improved soil nutrient status, which prompted this study of soil charge characteristics in the irrigated and control plots. Soil was an Alfisol, and thus it was not clear a prioriwhether variable-charge or permanent-charge components dominated. Surface soil (0–15 cm) had a pH(H2O) of 5.5 and pH(KCl) of 4.8. Subsurface soil (30–45 cm) had a pH(H2O) of 4.8 and a pH(KCl) of 3.5. The point of zero salt effect (PZSE), measured by titration, varied from 3.7 to 5.0 in surface soil and from 3.5 to 4.2 in subsurface soil. Variable charge of surface soil was 2.6 cmolc/kg.pH unit after the dry season in April versus 3.2 cmolc/kg.pH unit after the wet season in December in both control and dry-season irrigated plots, reflecting seasonal differences in pH and PZSE. The point of zero net charge (PZNC), measured by ion retention, was at pH <2.0, indicating that permanent-charge components dominated the soil surface charge. Five years of dry-season irrigation resulted in pH(H2O) increasing by 0.6 units and pH(KCl) increasing by 0.2 units. As well, irrigation increased the amount of permanent charge and cation retention, leading to less sorption of phosphate and sulfate. The results have important ecological implications, showing mechanistically how wetter conditions affected soil surface charge leading to improved soil nutrient status. permanent charge, soil pH, tropical forest soil, variable charge, water regime.

Electrostatic Adsorption of Cations

1997 ◽  
Author(s):  
G. L. Ji ◽  
H. Y. Li
Keyword(s):  
Surface Layer ◽  
Surface Charge ◽  
Electrostatic Interactions ◽  
Colloidal Particles ◽  
Bulk Solution ◽  
Potassium Ions ◽  
Electrostatic Adsorption ◽  
Variable Charge ◽  
Negative Adsorption ◽  
Variable Charge Soils

Adsorption of ions is a direct consequence of the carrying of surface charge for soils. Owing to the characteristics of variable charge soils in chemical and mineralogical compositions, these soils possess distinct amphoteric properties. Therefore, they can adsorb cations as well as anions. Under field conditions, most of the variable charge soils carry more negative surface charge than positive surface charge, hence they adsorb more cations than anions. Under certain conditions the quantities of adsorbed cations and anions are equal to each other. In this case the soil is said to be at its iso-ionic point. Generally, for most cations commonly found in soils, the interaction force between them and the surface of soil particles during adsorption is electrostatic in nature. However, owing to the characteristics of variable charge soils, a specific force may also be involved in the adsorption of some cations. This latter topic shall be discussed in Chapter 5. In this chapter, only electrostatic adsorption is dealt with. In the present chapter, the mechanism of electrostatic adsorption of cations by variable charge soils and the factors that may affect this type of adsorption are presented first. Then, the dissociation of adsorbed cations is discussed. Finally, the competitive adsorptions of potassium ions with sodium ions and of potassium ions with calcium ions are examined. According to the definition in physical chemistry, the concentration of solute in the surface layer of the solution is different from that in the interior of the bulk solution. If the concentration of solute in the surface layer is higher than that in the interior, the phenomenon is called adsorption. Conversely, it is called negative adsorption. In soil science, on the other hand, the heterogeneity in distribution of ions in soil colloidal systems is interpreted mainly in terms of electrostatic interactions occurring at the interface between soil colloidal particles and the liquid phase (Bear, 1964). Owing to adsorption or negative adsorption, the concentration of ions at the surface of soil colloidal particles or adjacent to the surface is higher or lower than that in the diffuse layer or the free solution.

Surface charge properties of variable charge soils influenced by environmental factors

2020 ◽  
Vol 189 ◽  
pp. 105522
Author(s):  
Xiaocui Wen ◽  
Ying Wang ◽  
Pengfei Cheng ◽  
Dong Liu ◽  
Siqi Ma ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Surface Charge ◽  
Variable Charge ◽  
Variable Charge Soils

scholarly journals Charge Characteristics and Cation Exchanges Properties of Hilly Dryland Soils Aceh Besar, Indonesia

2020 ◽  
Vol 9 (2) ◽  
pp. 90-101
Author(s):  
Sufardi Sufardi ◽  
Teti Arabia ◽  
Khairullah Khairullah ◽  
Karnilawati Karnilawati ◽  
Sahbudin Sahbudin ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Surface Charge ◽  
Organic Amendments ◽  
Chemical Properties ◽  
Soil Surface ◽  
Tropical Soils ◽  
Exchange Capacity ◽  
Surface Charges ◽  
Variable Charge ◽  
Negative Surface

Soil surface charge and cation exchange are important parameters of soil fertility in tropical soils. This study was conducted to investigate characteristics of surface charges and cation exchanges on four soil orders of the dryland in  Aceh Besar district. The soil order includes Entisols Jantho (05o16’58.41” N; 95o37’51.82” E), Andisols Saree (05o27'15.6" N; 95o44'09,1" E), Inceptisols Cucum (05º18’18,37” N; 95º32’48,04” E), dan Oxisols Lembah Seulawah (05o27’19,4” N; 95o46’19,2” E). The charge characteristics of surface charge are evaluated from the parameter of DpH (pHH2O-pHKCl), variable charge (Vc), permanent charge (Pc), and point of zero charges (PZC). In contrast, cation exchange properties are evaluated from several soil chemical properties, such as soil organic matter (SOM), base saturation (BS), cation exchange capacity (CEC), and effective CEC (ECEC). The results show that the four pedons of soil in the hilly dryland of Aceh Besar include a variable charge because it has a PZC, which is characterized by a negative surface charge with a PZC of pHH2O and has CEC dependent soil pH. PZC value varies from 3.21 – 5.26 and sequentially PZC Andisols Oxisols Entisols Inceptisols. The total CEC value differs considerably from ECEC and the sum of cations. CEC total of the soils varies from 12.8 – 34.4 cmol kg-1, whereas the ECEC values vary from 2.72 – 8.66 cmol kg-1. The highest variable charge percentage is found in Andisols Saree. In contrast, the highest permanent charge is found in Inceptisols Cucum and is positively correlated with pHH20, PZC, CEC, and sums of cations or ECEC. Improving soil quality in hilly dryland soils in Aceh Besar District can be done by decreasing the PZC status of soils with organic amendments and fertilizers or increasing the pH by using liming.

Surface Charge

1997 ◽  
Author(s):  
X. N. Zhang ◽  
A. Z. Zhao
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Clay Minerals ◽  
Chemical Properties ◽  
Surface Charges ◽  
Variable Charge ◽  
Surface Materials ◽  
Two Factors ◽  
Constant Charge ◽  
Variable Charge Soils

The surface of soil colloids carries electric charges, and these surface charges are the basic cause for soil to possess a series of surface properties. Soil surface charges affect the chemical properties of the soil through varying the quantity of electric charge and the surface charge density. For example, adsorptions of cations and anions are caused by negative and positive surface charges of the soil, respectively. The amount of ions adsorbed is determined by the quantity of surface charge, whereas the tightness of adsorption is related to charge density. In addition, the migration of ions in soil, the formation of organo-mineral complexes,and the dispersion, flocculation, swelling, and shrinkage are all affected by surface charge properties of the soil. Therefore, surface charge properties have an important bearing on soil structure and plant nutrition. Variable charge soils are characterized by the high content of iron and aluminum oxides. The clay mineralogical composition is dominated by 1:1-type minerals, such as kaolinite. These two factors make the surface charge properties of variable charge soils distinctly different from those of constant charge soils of temperate regions which chiefly containin 2:1-type clay minerals. However, unlike the case for pure variable charge minerals, in variable charge soils there is generally the presence of a certain amount of 2:1-type clay minerals. Therefore, as a mixture of variable charge minerals and constant charge minerals, the surface charge properties of variable charge soils is more complicated. In this chapter, the origin and factors affecting surface charges of the soil as well as the relationship between these charges and soil type will be discussed. Despite the complexity in composition, a soil may be regarded as a mixed system consisting of constant charge surface materials and constant potential surface materials in different ratios (Anderson and Sposito, 1992; Gillman and Uehara, 1980). Examples of the former type such as montmorillonite and vermiculite carry permanent negative charges, while those of the latter type such as iron oxide and aluminum oxide carry variable charges. Commonly found constant charge clay minerals in soils include those layer silicates such as hydrous mica, vermiculite, montmorillonite, and chlorite.

Chemistry of Variable Charge Soils

1997 ◽  
Keyword(s):  
Soil Pollution ◽  
Management Practices ◽  
Chemical Properties ◽  
Soil Management ◽  
Soil Productivity ◽  
Basic Difference ◽  
The Past ◽  
Variable Charge ◽  
Constant Charge ◽  
Variable Charge Soils

This book, based on research carried out at the Academia Sinica over the past 30 years, explains the basic difference between the variable charge soils of tropical and subtropical regions, and the constant charge soils of temperate regions. It will focus on the chemical properties of the variable charge soils--properties which have important bearing on soil management practices, including maximizing soil productivity and combating soil pollution.

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