Quaternized rice husk as sorbent for reactive dyes

A study on the sorption of hydrolyzed Reactive Blue 2 by quaternized rice husk showed that the binding capacity of the sorbent was not suppressed by dyebath conditions of high concentration of electrolytes. Its sorption capacity decreased with increasing concentration of NaOH. Complete regeneration of dye-coated quaternized rice husk was not possible under base treatment, suggesting chemisorption of dye molecules on the sorbent material. The physical stability of the quaternized rice husk was examined by treating it with various concentrations of NaOH solution. Results showed that no dissolution of sorbent occurred, even in 1 M NaOH solution

Arsenic Contents in Some Malaysian Vegetables

The arsenic content of forty-one common Malaysian vegetables was analysed by hydride generation-inductively coupled plasma emission spectrometry. None of the samples showed level greater than 2.00 J.1 g {fJ. The highest was found in bean sprouts (Phaseolus radiatus) (2.00 J.1 g {fl) and the lowest in sengkuang (Pachyrrhizus erosus) (0.20 J.1 g {fl). Boiling caused a loss of 17 to 60% arsenic in the plants

Cadmium uptake by the moss, Calymperes delessertii, Besch

Studies were conducted to assess the capability of a moss, Calymperes delessertii Besch, in removing cadmium from solutions. In the batch experiments, parameters studied included pH, sorbent dosage, cadmium concentration, ionic strength, presence of other ions, temperature and contact time. In addition, a series of fixed-bed experiments was performed to study the flow system in an attempt to simulate industrial conditions. The bed depth service time (BDST) model proposed by Hutchins was successfully applied to the system. The results show that the moss is an efficient sorbent for cadmium from solution and that the mechanism of sorption is mainly an ion-exchange process

An Evaluation of an Inductively Coupled Plasma (ICP) Emission Spectrometer

The performance of an Inductively Coupled Plasma (ICP) emission spectrometer was evaluated in' terms of its monochromator resettability, ICP generator stability and detection limits. The studies showed that the analytical system exhibited similar performance to simultaneous direct reading spectrometers. The reliability of the monochromator, torch heigh t adjustor and the stability of the source unit were confirmed

Removal of metals from electroplating wastes using banana pith

Banana pith (Musacea zingiberales) was evaluated for its ability to sorb metal ions from electroplating waste and synthetic solutions under both batch- and continuous-flow conditions. Sorption was both pH and concentration dependent, with pH 4·5 being the optimum value. The equilibrium data followed the Langmuir isotherm model with maximum capacities of 8·55 and 13·46 mg/g for Cu in electroplating waste and synthetic solution respectively. Competitive studies showed that the affinity of metal sorption was in the order Pb(II) > Cu(II) > Ni(II) > Cr(III) > Zn(II). In the continuous-flow studies, breakthrough curves for Cu(II) and Ni(II) in the elctroplating waste were obtained at different bed depths and flow rates. Cu(II) was more satisfactorily sorbed on the banana pith than Ni(II)

Quaternized wood as sorbent for hexavalent chromium

The potential of quaternized wood (QW) chips in removing hexavalent chromium from synthetic solution and chrome waste under both batch and continuous-flow conditions was investigated. Sorption was found to be dependent on pH, metal concentration, and temperature. QW chips provide higher sorption capacity and wider pH range compared with untreated wood chips. The equilibrium data could be fitted into the Langmuir isotherm model, and maximum sorption capacities were calculated to be 27.03 and 25.77 mg/g in synthetic chromate solution and chrome waste, respectively. The presence of sulfate in high concentration appeared to suppress the uptake of chromium by QW chips. Column studies showed that bed depth influenced the breakthrough time greatly whereas flow rate of influent had little effect on its sorption on the column

Carbonized spent bleaching earth as a sorbent for some organic dyes

The potential of carbonized spent bleaching earth (CSBE) to remove/reduce acid and basic dyes in aqueous solution was investigated. Results show that CSBE was more effective in removing basic dyes. Parameters like pH, initial concentration, agitation rate, contact time and temperature which affect the sorption process were studied. As determined from Langmuir isotherms the maximum sorption capacities of CSBE for Basic Blue 3 and Methylene Blue were 102.6 and 94.5 mg/g respectively. Hence CSBE could be a useful sorbent in the treatment of baisc dyes in wastewater

Quaternized wood as sorbent for reactive dyes

Various species of local wood modified with N-(3-chloro-2-hydroxypropyl)-trimethylammonium chloride showed sorption enhancement for hydrolyzed Reactive Blue 2 (HRB) compared to the untreated samples. The enthalpy of sorption of HRB on Simpoh (Dillenia suffruticosa) was found to be endothermic. Maximum sorption capacity calculated from the Langmuir isotherm was 250.0 mg/g. Under continuous flow conditions HRB could be successfully removed. Dye removal was a function of bed depth and flow rate. However, the bed depth service time model of Bohart and Adams was not applicable in the HRB-quaternized wood system. The modified wood was applied to a sample of industrial textile effluent, and it was found to be able to remove the color successfully under batch conditions

Sorption of cadmium and lead from aqueous solutions by spent grain

The sorption of cadmium and lead from aqueous solutions by spent grain, a by-product of the brewing process, was investigated. The effects of solution pH, ionic strength, initial concentration, ligands and temperature were studied in batch experiments. The equilibrium process was described well by the Langmuir isotherm model with maximum sorption capacities of 17.3 and 35.5 mg/g of cadmium and lead on spent grain, respectively. The enthalpy of sorption was endothermic and the increase in Pb uptake was larger than that of Cd over the same rise in temperature. The initial uptake was rapid and equilibrium was established in less than 120 min. Good correlation coefficients were obtained for the pseudo second-order kinetic model. Equimolar concentrations of Cd and Pb to ethylenediamine tetraacetic acid and nitrilotriacetic acid almost completely suppressed the uptake of metals. Sorption capacities of spent grain for cadmium and lead were compared with some low-cost biological materials