Removal of dyes from wastewaters by low-cost adsorbents

Dyes represent an objectionable pollutant to the environment. The removal of dyes has been of great concern because of their toxicity and persistency. The usage of commercial activated carbon to remove dyes in wastewater is limited due to its high cost. This prompted the search for alternative low-cost adsorbents. This chapter examines (i) historical aspects and pollution issues concerning dyes; (ii) main treatment technologies and their limitations; (iii) various studies using waste materials from agriculture and industry or naturally occurring biosorbents; and (iv) equilibrium and kinetic models used in batch and continuous systems that are important for design purpose

Dye Waste Treatment

© 2011 by the authors. Dye wastes represent one of the most problematic groups of pollutants because they can be easily identified by the human eye and are not easily biodegradable. This literature review paper highlights and provides an overview of dye waste treatments performed over the three years period from 2008-2010. Noteworthy processes for the treatment of dye waste include biological treatment, catalytic oxidation, filtration, sorption process and combination treatments

Removal of Hazardous Heavy Metals From Aqueous Environment by Low-Cost Adsorption Materials

The rapid growth of the human population and industrialization in the world has indirectly increased environmental problems such as water, air and land pollution. Amongst all, heavy metals can be considered as the most problematic pollutants. Numerous efforts have been attempted to minimize the impact of heavy metals. This chapter discusses the recent developments and technical applicability of different treatment methods for heavy metal removal. The adsorption process using various low-cost materials as the potential alternative for heavy metal removal is being highlighted and summarized

Leukaemia exposure alters the transcriptional profile and function of BCR::ABL1 negative macrophages in the bone marrow niche

Macrophages are fundamental cells of the innate immune system that support normal haematopoiesis and play roles in both anti-cancer immunity and tumour progression. Here we use a chimeric mouse model of chronic myeloid leukaemia (CML) and human bone marrow (BM) derived macrophages to study the impact of the dysregulated BM microenvironment on bystander macrophages. Utilising single-cell RNA sequencing (scRNA-seq) of Philadelphia chromosome (Ph) negative macrophages we reveal unique subpopulations of immature macrophages residing in the CML BM microenvironment. CML exposed macrophages separate from their normal counterparts by reduced expression of the surface marker CD36, which significantly reduces clearance of apoptotic cells. We uncover aberrant production of CML-secreted factors, including the immune modulatory protein lactotransferrin (LTF), that suppresses efferocytosis, phagocytosis, and CD36 surface expression in BM macrophages, indicating that the elevated secretion of LTF is, at least partially responsible for the supressed clearance function of Ph- macrophages

Plackett-Burman design and response surface methodological approach to optimize basic dyes removal using sugarcane bagasse

Plackett-Burman design was applied to identify the most significant factors in the removal of Basic Blue 3 (BB3), Methylene Blue (MB) and Basic Yellow 11 (BY11) by natural sugarcane bagasse. The effect of operating parameters on dye uptake was studied in a batch system and a mathematical model showing the influence of each variable was obtained. The interaction between the factors and their optimum levels for maximum percentage uptake of BB3 and MB were determined using Response Surface Methodology (RSM). Both models were highly significant with correlation coefficients (R 2) of 0.9932 and 0.9944 for BB3 and MB, respectively in binary dye solution. For BB3, the optimum adsorption conditions were determined as initial pH 6.00, contact time 122.50 min, initial dye concentration 50 mg/L and sorbent dosage 0.09 g. Whereas for MB, the model predicted that an uptake greater than 90% could be obtained when the initial dye concentration, contact time and sorbent dosage were set at 80.40 mg/L, 192.37 min and 0.17 g, respectively. The percentage uptake predicted by the model was in good agreement with the experimental values

Application of response surface analysis for optimization of dyes sorption onto EDTA modified rice hull

The batch removal of basic and reactive dyes from aqueous solution using ethylenediamine tetraacetic acid modified rice husk (ERH) was studied. Plackett-Burman design coupled with response surface methodology (11SM) were adopted to evaluate the effect of various operating parameters, such aspH (2-10), contact time (5-420 mins) andsorbent dosage (0.05-0.2g) on the percentage of dye removal. The optimum adsorption conditions for Methylene Blue were determined as pH: 8.6, contact time: 131 mins and sorbent dosage: 0.13g. As for Reactive Orange 16, a greater uptake was observed at a lower pH. The empirical model developed from the interactive effects of important operating variables was validated using ANOVA analysis. The percentage uptakes predicted by the model are in good agreement with the experimental values, thus confirming the reliabilily of the models

Equilibrium studies and kinetics mechanism for the removal of basic and reactive dyes in both single and binary systems using EDTA modified rice husk

The potential of using ethylenediamine tetraacetic acid modified rice husk (ERH) to remove different types of dyes, namely basic and reactive dyes were studied. Sorption characteristic of ERH showed that it was pH dependent. The kinetics of sorption for both dyes was rapid within the first 60 min regardless of its initial concentration. Using the pseudo-second order kinetics model, the predicted uptakes of Methylene Blue (MB) and Reactive Orange 16 (RO16) agreed closely with experimental values obtained. Three isotherm models were used to fit with equilibrium data, namely Langmuir, Freundlich and BET models. It was found that the equilibrium fitted well in Freundlich isotherm with higher regression coefficient value, R2. Thermodynamic parameters showed that the sorption of process of MB and RO16 are exothermic and endothermic, respectively. Decrease in sorbent particle size led to an increase in the sorption of dyes. The study revealed that ERH is suitable to use as a single sorbent to remove both MB and RO16 in all systems

Removal of hazardous heavy metals from aqueous environment by low-cost adsorption materials

The rapid growth of the human population and industrialization in the world has indirectly increased environmental problems such as water, air and land pollution. Amongst all, heavy metals can be considered as the most problematic pollutants. Numerous efforts have been attempted to minimize the impact of heavy metals. This chapter discusses the recent developments and technical applicability of different treatment methods for heavy metal removal. The adsorption process using various low-cost materials as the potential alternative for heavy metal removal is being highlighted and summarized

Removal of Heavy Metals by Low-Cost Adsorption Materials

© 2018 by Taylor & Francis Group, LLC. Owing to the environmental impact as well as the growing awareness among the public, it is imperative to remove or reduce the concentration of heavy metals to environmentally acceptable levels before being discharged to open stream. The conventional methods for removing heavy metals suffer from many drawbacks such as high cost, sludge disposal problem, complex technology, and limited applicability. Therefore, intensive research has been carried out using low-cost materials to remove these heavy metals at an affordable cost. This chapter examines (i) some commonly found heavy metals in wastewater, (ii) main treatment technologies and their limitations, (iii) various studies using waste materials from agriculture and industry or naturally occurring biosorbents, (iv) chemical properties and characterization studies on the low-cost adsorbents, (v) influential parameters in affecting the removal efficiency, and (vi) equilibrium, kinetic models, and process design used in the adsorption process