Raw wheat bran (R-WB) was used as a biomass adsorbent. The properties of R-WB were investigated. Moreover, the adsorption of cadmium and lead ions onto R-WB was evaluated. Adsorption equilibrium of cadmium and lead ions onto R-WB was achieved within 10 h, indicating that the adsorption followed a pseudo-second-order model rather than a pseudo-first-order kinetic model. Consequently, polluted water could be successfully purified by using a column filled with this bioadsorbent.

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In this study, we investigated the surface properties of granulated boehmite with vinyl acetate (G-BE20) and measured the amount of phosphate it adsorbed and the effect of contact time and solution pH on the adsorption process. The specific surface area (144.9 m 2 /g) and the number of surface hydroxyl groups (0.88 mmol/g) of G-BE20 were smaller than those of virgin boehmite (BE), which gave a specific surface area and number of surface hydroxyl groups of 297.0 m 2 /g and 1.08 mmol/g, respectively. The amount of phosphate adsorbed increased with the temperature. The isotherm model of Langmuir was used to fit experimental adsorption equilibrium data for phosphate adsorption onto G-BE20. The calculated thermodynamic parameters show the spontaneous and endothermic nature of the adsorption process. The equilibrium adsorption onto G-BE20 was reached within 16 h and the amount of phosphate adsorbed was 8.4 mg/g. The kinetic mechanism of phosphate uptake was evaluated with two different models: the Largergren pseudo first-and pseudo second-order models. The data obtained showed a better fit to the pseudo second-order model (0.991) than to the pseudo first-order model (0.967), as indicated by the r values. The rate constants for the adsorption of phosphate onto G-BE20 were calculated as 0.481 1/h and 0.029 g/mg h. The adsorption of phosphate onto G-BE20 was the maximum in the pH range 3.0-4.0. Key words phosphate; adsorption; boehmitePhosphorus is an important nutrient involved in several biochemical reactions, and it cannot be substituted by other elements. It is widely used in agriculture and industry.1) The presence of trace amounts of phosphorus, exceeding about 1 mg/L, in treated wastewater can stimulate algal growth (eutrophication); phosphorus is usually considered a rate-limiting factor for algal growth.2) Algal blooms lead to short-and longterm environmental and aesthetic problems in lakes, coastal areas, and other confined water bodies.3) Moreover, phosphate is an exhaustible resource, and Japan depends solely on imports owing to a lack of native rock phosphate. As a consequence, phosphate removal and recovery from wastewater has been considered an important factor related to environmental sustainability. 4)Several physicochemical and biological processes have been investigated for the removal of dissolved nutrients in water and wastewaters. 5-9) They include adsorption methods, physical processes (settling and filtration), chemical precipitation (with aluminum, iron, and calcium salts), and biological processes that rely on biomass growth (bacteria, algae, and plants) or intracellular bacterial polyphosphate accumulation.10) Adsorption is one of the most attractive approaches in water treatment, and it has the advantage of having high removal efficiency without producing harmful by-products. 11)It is also well known that phosphates have a strong affinity for mineral surfaces.12) Its affinity for hydroxide surfaces depends not only on the anion's complexing capacity, which allows phosphates to bind to surface ...

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In this study, we investigated the surface properties of raw wheat bran (R-WB) and wheat bran treated with Pectinase PL (P-WB) to evaluating its efficacy for removal of cadmium from waste water. The concentration of cadmium ions adsorbed by them was evaluated. The concentration of carboxyl groups of R-WB (3.56 mmol/g) was greater than that of P-WB (2.11 mmol/g), which indicated that the pectin of R-WB was broken down, resulting in a decrease in the concentration of carboxyl groups due to the enzyme treatment. From the scanning electron microscope (SEM) images of P-WB, the pores were newly generated with enzyme treatment. The concentration of cadmium ions adsorbed onto R-WB was greater than that of cadmium ions adsorbed onto P-WB. These results show that the adsorption mechanism of cadmium ions onto R-WB and P-WB depends on the carboxyl groups of pectin.