Bentonite Zeolite Research Articles

Preparation and characteristics of bentonite–zeolite adsorbent and its application in swine wastewater

The preparation of bentonite–zeolite (BZ) adsorbent using bentonite, aluminate, and rice husk was conducted. The adsorption experiment was performed for the removal of Cu2+ and Zn2+ from aqueous solution in single and binary systems. Results showed that gasification of rice husk could effectively improve the specific surface area and pore volume. The optimum pH for Cu2+ and Zn2+ adsorption on BZ was pH 5.0. The pseudo-first order kinetic and Langmuir isotherm model of BZ were the optimal model for Cu2+ and Zn2+. According to Langmuir isotherm model, the maximum adsorption capacity value (qm) was 16.39 and 12.72 mg·g−1 for Cu2+ and Zn2+, respectively. The adsorption affinity order of BZ in the binary solution was Cu2+ > Zn2+. NH4+-N concentration over 500 mg·L−1 significantly affected the adsorption capacity of BZ (P < 0.05). The adsorption capacity of BZ for Cu2+ and Zn2+ was higher than that artificial zeolite (AZ) and bentonite in SW.

Geomechanics of Landfills—Innovative Technology for Liners

Cracks in clayey landfill liner, which cannot be closed up upon re-wetting, affect the long-term performance of a landfill. In this paper, the mixture bentonite-zeolite (BEZ) is presented as a potential liner material due to its plastic properties. Also, it may fulfill an existing demand, in developing countries, for liners that are cost-effective, natural and in compliance with environmental regulations. Traditional liners have shortcomings: (i) clayey soil is suitable for liners if the temperature and moisture fluctuations are not high; otherwise, they may form cracks; (ii) geomembranes, considered as the best alternatives for liners, are out of reach of most underdeveloped countries for their high price, and do not last more than 4 years; (iii) the interface of a CGL (clay geosynthetic liner) is susceptible to sliding. In the studies performed, the low volumetric shrinkage of the BEZ indicates that it is not affected by moisture content fluctuations, and its hydraulic conductivity in the order of 10 −10 cm/s meets regulatory agency requirements. Also, its inherent chemical properties (specially clinoptilolite zeolite) and its natural selectivity indicates that it will adsorb heavy metals such as Pb 2+ , Zn 2+ , Cd 2+ , Ni 2+ ,Fe 2+ , and Mn 2+ that may be present in leachate. Therefore, BEZ is a potential innovative material for liners in landfills.

Effects of pseudogley chemical amelioration on the changes in soil and plant phosphorus and potassium contents

Pseudogley is a soil type that is under natural conditions characterized by unfavorable properties, the most pronounced being insufficient amounts of basic plant nutrients. Using different amelioration measures, numerous researchers have tried to overcome the problems resulting from soil acidity (increased aluminum and manganese contents, deficiency of alkaline cations in the adsorption complex and reduced available phosphorus content). Calcification was the most common measure almost always producing the best results of all the measures. In order to determine the effect of some neutralization acidity materials derived from natural sources (bentonite zeolite, lifos, CaO and MgO) on the change in the available phosphorus and potassium contents, a trial was set up on extremely acid soil to determine the manner of change in the nutrients concentrations in maize leaf and grain. The results obtained show that all ameliorative measures used affected the soil phosphorus and potassium contents increase, depending on the reduction of acidity and the mobile aluminum content, resulting also in a better uptake of the nutrients from the soil.