Why Dye Wastewater is Dangerous

Why dye wastewater is dangerous? Wastewater could spread into environmental and become hazardous to living organism. The dyeing substance that are used in textile industry gives colour to the water. Colored textile wastewater accumulates in water environment and deteoriates the aesthetic appearance of the waterand decreases the light permeability. Decrease in the light permeability and the amount ofdecomposed oxygen causes the extinction of living beings and restricts the reuse of the water. Furthermore it is known that some dying substance contain toxic materials .Not only the dyes but also wastewater caused by chemical materials cause vital problems. For this reasons refining the textile industry wastewater is very important.

Why methylene blue is the stress in the journal? Most frequently used dyes in all industries

May cause eye burns, irritations to the gastrointestinal, vomiting, diarrhea, irritation to the skin

What is methylene blue? Organic dye

What is Activated Carbon?Activated carbon, also known as activated charcoal, is a crude form ofgraphite, the substance used for pencil leads. It differs from graphite by having a random, imperfect structure which is highly porous over a broad range of pore sizes from visible cracks and crevices to molecular dimensions. The graphite structure gives the carbon its very large surface area which allows the carbon to adsorb a wide range of compounds.Activated carbon(activated charcoal) has the strongest physical adsorption forces, or the highest volume of adsorbing porosity, of any material known to mankind.Activated carbon (activated charcoal) can have a surface of greater than 1000m/g. This means 3g ofactivated carboncan have the surface area of a football field.What is adsorption ?Adsorption is the process by which liquid or gaseous molecules are concentrated on a solid surface, in this case activated carbon (activated charcoal). This is different from absorption, where molecules are taken up by a liquid or gas.Click herefor more information on adsorption.What is activated carbon made from ?Activated carbon (activated charcoal) can made from many substances containing a high carbon content such as coal, coconut shells and wood. The raw material has a very large influence on the characteristics and performance of the activated carbon (activated charcoal).Forms of activated carbonThere are three main forms of activated carbon (activated charcoal).Granular Activated Carbon (GAC)- irregular shaped particles with sizes ranging from 0.2 to 5 mm. This type is used in both liquid and gas phase applications.

Powder Activated Carbon (PAC)- pulverised carbon with a size predominantly less than 0.18mm (US Mesh 80). These are mainly used in liquid phase applications and for flue gas treatment.

Extruded Activated Carbon(EAC)- extruded and cylindrical shaped with diameters from 0.8 to 5 mm. These are mainly used for gas phase applications because of their low pressure drop, high mechanical strength and low dust content.

Charcoal Activated Carbon Cloth (ACC)- Activated carbon is also available in special forms such as a cloth and fibres.

Activated Carbon Briquettes (ACB)- Activated carbons can be agglomerated and formed into a variety of briquettes.

"The Customer Can Have Any Color He Wants So Long As It's Black". - Henry Ford- If you need activated carbon in a different colour pleasecontact usto discuss your requirements.

Adsorption / Active CarbonActivated carbon adsorptionAdsorption is a process where a solid is used for removing a soluble substance from the water. In this process active carbon is the solid. Activatedcarbonis produced specifically so as to achieve a very big internal surface (between 500 - 1500 m2/g). This big internal surface makes active carbon ideal for adsorption. Active carbon comes in two variations: Powder Activated Carbon (PAC) and Granular Activated Carbon (GAC). The GAC version is mostly used in water treatment, it can adsorb the following soluble substances:Datasheet Active Carbon Adsorption of organic, non-polar substances such as: Mineral oil BTEX Poly aromatic hydrocarbons (PACs) (Chloride) phenol Adsorption of halogenated substance: I, Br, Cl, H en F Odor Taste Yeasts Various fermentation products Non-polar substances (Substances which are non soluble in water)

Examples from active carbon in different processes: Ground water purification The de-chlorination of process water Water purification for swimming pools The polishing of treated effluentProcess description:Water is pumped in a column which contains active carbon, this water leaves the column through a draining system. The activity of an active carbon column depends on the temperature and the nature of the substances. Water goes through the column constantly, which gives an accumulation of substances in the filter. For that reason the filter needs to be replace periodically. A used filter can be regenerated in different ways, granular carbon can be regenerated easily by oxidizing the organic matter. The efficiency of the active carbon decreases by 5 - 10% 1). A small part of the active carbon is destroyed during the regeneration process and must be replaced. If you work with different columns in series, you can assure that you will not have a total exhaustion of your purification system.Description of adsorption:Molecules from gas or liquid phase will be attached in a physical way to a surface, in this case the surface is from the active carbon. The adsorption process takes place in three steps: Macro transport: The movement of organic material through the macro-pore system of the active carbon (macro-pore >50nm) Micro transport: The movement of organic material through the meso-pore and micro-pore system of the active carbon (micro-pore 50 nm diameter) Mesopores (2-50 nm diameter) Micropores (< 2 nm diameter)Micropores generally contribute to the major part of the internal surface area. Macro and mesopores can generally be regarded as the highways into the carbon particle, and are crucial for kinetics. Macropores can be visualized using scanning electron microscopy.The most common process is high temperature steam activation though it can also be manufactured with chemicals. Along with the raw material, the activation process has a very large influence on the characteristicsand performance of activated carbon.Our main line of granular activated carbons are produced by steam activation of selected grades of pulverised andthenre-agglomerated bituminous coal. Our powder activated carbon is mainly producedby pulverisation of the final product.Benefits of this process: A pore structure containing a good mix of both larger transport pores and smaller adsorption pores giving both high capacity and good kinetics. This results in excellent adsorption in a wide range of applications such as decolourisation and water treatment. The transport pores between the agglomerated particles allow the activation gases to penetrate much more within the structure of the activated carbon. The whole granule, not just the outside, is activated. Combined with the high mechanical strength of the coal base, these transport pores also give the carbon excellentreactivationperformance. This process ensures the carbon can be rapidly wetted for easy application in liquid phase applications. By producing from a pulverised blend, the granules used in the activation process are more uniform resulting in consistent high quality products.A surface already heavily contaminated by adsorbates is not likely to have much capacity for additional binding. Freshly prepared activated carbon has a clean surface. Charcoal made from roasting wood differs from activated carbon in that its surface is contaminated by other products, but further heating will drive off these compounds to produce a surface with high adsorptive capacity. Although the carbon atoms and linked carbons are most important for adsorption, the mineral structure contributes to shape and to mechanical strength. Spent activated carbon is regenerated by roasting, but the thermal expansion and contraction eventually disintegrate the structure so some carbon is lost or oxidized.Carbonaceous materials are activated using two methods: Steam activation Chemical activation

Steam ActivationSteam activation is the most widely used process to activate carbonaceous materials. Steam activated carbons are produced in a two-stage process. First, the raw material in the form of lumps, pre-sized material, briquettes or extrudates is carbonized by heating in an low oxygen atmosphere so that dehydration and devolatilization of the raw material occurs. Carbonization reduces the volatile content of the source material to under 20%. A coke or charcoal (depending on the raw material) is produced which has pores that are either small or too restricted to be used as an adsorbent.

The second stage, which can take place later in the same kiln, is activation which enlarges the pore structure, increases the internal surface area and makes it more accessible. The carbonized product is activated with steam at very high temperatures. The chemical reaction between the carbon and steam takes place at the internal surface of the carbon, removing carbon from the pore walls and thereby enlarging the pores.

The steam activation process allows the pore size to be readily altered and carbons can be produced to suit specific end uses. The pore structure has to be opened up more for the adsorption of small molecules from a solution, as in water purification, than for the adsorption of large color molecules in sugar decolorization.Gas phase activated carbons are more difficult and expensive to produce than liquid phase carbon since they require a longer time inside the activation furnace.

Chemical ActivationChemical activation is generally used for the production of activated carbon from sawdust, wood or peat. The process involves mixing an organic chemical compound with the carbonaceous raw material, usually wood, and carbonizing the resultant mixture.The raw material is mixed with an activating agent, usually phosphoric acid, to swell the wood and open up the cellulose structure. The paste of raw material and phosphoric acid is dried and then carbonized, usually in a rotary kiln, at a relatively low temperature of 400 to 500 degree Celsius. On carbonization, the chemical acts as a support and does not allow the charcoal produced to shrink. It dehydrates the raw material, resulting in the charring and amortization of the carbon, thereby creating a porous structure and an extended surface area.Activated carbons produced by this method have a suitable pore distribution to be used as an adsorbent without further treatment. The process used means that the activated carbons are acid washed carbons although they have a lower purity than specifically acid washed steam activated carbons. This chemical activation process normally yields a powdered activated carbon. If granular material is required, granular raw materials are impregnated with the activating agent and the same method is used. Granular activated carbons (GACs) produced have a low mechanical strength, and are not suitable for many gas phase uses. In some cases, chemically activated carbons are given a second activation with steam to impart additional physical properties.