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This study utilizes sugar beet pulp as a low-cost absorbent to remove two different cationic dyes, methylene blue and safranin, in aqueous solutions. The effects of operational parameters on the efficiency of dye removal including pH, adsorbent mass, initial dye concentration and contact time have been investigated. All sets of experiments were carried out in batch mode. For both dyes, the maximum absorption was reached at pH 10 while point zero charge was known to be at pH 6. Boehm method showed that the amount of the acidic and basic groups have been 0.4075 mmol g−1 and 0.0089 mmol g−1, respectively. Freundlich and Langmuir models were used to analyse the obtained experimental data. In comparison, Langmuir model was understood to be a better fit for the experimental data than Freundlich model. Pseudo first-order and pseudo second-order models were used to determine the adsorption kinetics and it was observed that pseudo second-order model was the most suited model for both dyes. The equilibrium state for both dyes was reached after 210 min of the absorption experiment with more than 93% removal of dyes. The absorption capacities were found to be 211 mg/g and 147 mg/g for methylene blue and safranin, respectively.

In this study , Safranine absorption onto mango seed integuments (raw and NaOH treated) has been investigated. The effects of solution pH, initial dye concentration, contact time, point zero charge and surface chemistry of the adsorbent were studied batch-wise. Safranine adsorption onto the untreated sample is influenced by the pH of the aqueous solution whereas, adsorption with the NaOH- treated sample is independent of the pH of the solution. Boehm titration showed the acidic groups of the treated sample has a higher value (0.660 mmol/g) than the untreated sample (0.375 mmol/g). Freundlich isotherm model resulted in the best data fitting for the untreated sample. However, Langmuir model indicated the best fitting with the NaOH-treated sample. The adsorption kinetics was found to obey pseudo second order kinetic model for both samples. An approximate increase of 26 % was found in the amount of dye adsorption due to the treatment with NaOH.

A real leachate sample, taken from a Kuala Lumpur suburban area, was used in order to investigate the efficiency of electrocoagulation using Fe electrodes as both cathodes and anodes to reduce chemical oxygen demand (COD) and color of the sample. The effects of pH value and current density on the efficiency of the leachate treatment were investigated. Meanwhile, it was well understood that using this approach for the treatment of the studied leachate could successfully lower the COD value and color of the leachate wastewater by 81% and 72%, respectively. To the knowledge of the authors, to date, no real leachate samples have been treated by electrocoagulation methods elsewhere. Reference (2) has extensively covered the advantages and drawbacks of various contemporary approaches in landfill leachate treatments. Compared to current treatment processes available today, electrocoagulation can benefit from equipment simplicity; potable, clear, colorless and odorless treated product (6); much larger and stable flocs containing less bound water showing sufficient acid resistance compared to chemical flocs which enables them to be filtered by means of membranes; production of effluents with less total dissolved solids (TDS) content compared to chemical treatments which results in lower water recovery cost in case of water reuse (8); the capability of removing the smallest colloidal particles due to the facilitated coagulation by means of applied electric field (5 ); the absence of chemicals and as a result no secondary pollution which is common in membrane cleaning processes and many other treatment systems. Reference (6) investigated the use of electrocoagulation to treat landfill leachate using surface response methodology. They studied the effects of current density, pH, time and fluid conductivity and the interaction between them to get an optimal turbidity removal. Reference (7) used aluminium plates to electrocoagulate a leachate which had showed low biodegradability and high concentration of macromolecules and then made a quantitative comparison with classical coagulation-flocculation with aluminium ions and also electrolysis alone. This article investigates the application of electrocoagulation in the treatment of a real sample of landfill leachate. The experiments in this study were all carried out in a batch mode in order to evaluate the effects of different operational variables including leachate pH and current density and their effects on the COD and color removal of the leachate wastewater.

In this study the effect of physical mixing cigarette filters with KOH powder on the characteristics of the final carbonized porous carbon has been evaluated. The results were compared to that without any impregnation. The final carbonized product was studied using scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and adsorption-desorption analysis. It was found that dry KOH physical mixing of cigarette filters would decrease the specific Brunauer, Emmet, and Teller (BET) surface area by around 79%. This suggests that dry KOH impregnation of cigarette butts as carbon precursor for the synthesis of porous carbon would not be a suitable approach in obtaining higher BET surface area.