توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Comparing the capability of modified zeolite and a synthetic resin to remove toxic ion species from aquaculture effluents
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۷
Natural zeolites can have three major roles in aquaculture: (i) removing ammonia from ambient living
water; (ii) producing oxygen to aerate water bodies; (iii) as a filler included in feed. Systems capable of
removing undesired anions from wastewater effluents, even at extremely low concentrations, are a major
need in the industry. At the present study the natural zeolite was characterized using XRD and XRF analyses.
Modification was practiced with benzyl dimethyl tetradecyl ammonium chloride (BDTA) to increase the
adsorption of neothorin (on the zeolite), C10H11AsN2Na2O11S2, which subsequently increase ion exchange
capacity of zeolite per se. A cationic resin (sephadex®) was also applied. The effect of pH on the adsorption
of ions has also been evaluated. Result showed that clinoptilolite treated with BDTA was more efficient in
removing undesired ions from aquaculture wastewater. The selectivity sequences CrO4
2–>SeO4
2–>NO3
–>SO4
2–
>NO2–>PO4
3– and CrO4
2–>SeO4
2– > SO4
2–> PO4
3–> NO3
–> NO2
– were determined for clinoptilolite and resin,
respectively. Results showed that modified zeolite had more capability to remove phosphorus, nitrite and
nitrate than resin (p< 0.05). The optimum range of pH for both zeolite and resin for ions CrO4
2–, SO4
2–, SeO4
2–
, PO4
3–, NO2
– and NO3
– were 6.5 – 7.5, 5.5 – 7, 5.8 – 7.5, 5.5 – 7.2, 5.5 – 7 and 6 – 7, respectively.
Concludingly, due to lower cost of zeolite and its ability to remove common toxic species, namely,
phosphorus, nitrite and nitrate, it is recommended for more detailed studies.<\div>

۲Synthesis, characterization and use of Silica Gel Phases with chemically immobilized 2–Aminothiophenol for pre–concentration and determination of trace amounts of lead by Flame Atomic Absorption Spectrometry
اطلاعات انتشار: همایش بین المللی ژئولیت ایران، سال
تعداد صفحات: ۸
Developing an appropriate, cost effective and at–hand method for determination of trace amounts of
heavy metals in the water bodies is an on–demanding job due to the rate of present industrialization and the
need for aquatic ecosystem health monitoring. An analytical method using silica gel chemically modified
with 2–aminothiophenol for pre–concentration and subsequent determination of lead using flame atomic
absorption spectrometry (FAAS) was developed. In order to determine optimum conditions of quantitative
solid phase extraction of lead by 2–aminothiophenolpropyletrimetoxysilane (AmPTMS), parameters such as
pH and flow rate were investigated. The aromatic group, 2–Aminothiophenol can be utilized in grafting
reactions of silica gel surface, using 3–chloropropyletrimetoxysilane as a bridging molecule. Optimum
conditions for pH and flow rate of recovery and pre–concentration of lead from its aqueous solution were 5.0
and 1.0 ml min–1, respectively. A 4.12 ng\ml detection limit for the pre–concentration of aqueous solution of
lead was obtained. AmPTMS showed to be an efficient system for metal pre–concentration. The proposed
method was simple, accurate and cost effective, especially when more sophisticated techniques such as GFAAS
or ICP–OES are not available. The proposed procedure has been successfully applied for lead
determination at μg levels in industrial and river water samples.<\div>
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