Green chemistry application pdf

Gold is an outstanding catalyst for oxidation processes [4]. E-factor Environmental acceptability measures the ratio of the mass of waste to that of the product [5]. All processes should aim for the lowest possible E-factor - for truly green processes, the E-factor should be zero. Large-scale manufacturing units for bulk chemicals may generate large amount of waste, but their E-factors may be smaller than those of small-scale units as the E-factor depends on the quantity of waste in relation to total production.

Perfection of the Systems: A perfectly green process may not be so green if it hasn't been applied in the right situations. Fields of Application: The application of green chemistry is not restricted. Longevity: Green chemistry often remains unchanged for long periods of time. Overall Performance: Traditional purification and separation methods both generate large amounts of acid, base, and solvent wastes, and are often energy intensive. The utilization of rayon for clothing affects fast depleting forests.

Petroleum-based synthetic fibre and the dyes are not sustainable and not biodegradable [13]. Water Consumption Estimated total water used in wet processing of cellulosic fibres is 2. Water can be saved in dyeing in the following ways: 1 Reuse dyehouse water 2 Reduce reprocessing 3 Optimise rinsing and soaping processes 4 Reduce Liquor ratio Polluting Wet Processes The important environmental concerns related to textile wet processing are: 1 Chemical intensive wet processing— scouring, bleaching, mercerising, dyeing, printing etc.

Many of the chemicals used in textile processing can be recovered from waste water by membrane technology. The most problematic pollutant is the dye itself. Inherent to their purpose, dye molecules are designed to be resistant to degradation by light, water and many chemicals [14].

Dye molecules can be decomposed in water by a range of chemical, physical and biological treatments. The most widely used technique is the oxidative process, where hydrogen peroxide is added to the water and activated by ultra violet light to oxidise the dye molecules.

However, toxic sludge is produced, which has to be disposed of or incinerated. Adsorbable organic halogens AOX It is a measured value for organically bound chlorine, bromine and iodine in a given substance.

The AOX consent limit is likely to be as low as 2 ppm from a German drinking water directive DIN , [15] and as such compounds having high AOX values are to be used carefully, a few such products used in the textile industry are: 1 Chlorine-containing bleaching agent. Harmful Chemicals Some of the toxic and harmful substances used in textile industries and their eco-friendly substitutes are listed in Table 1 [16]: Table 1. Some examples of green approaches in various textile related industries are as follows: Greener Fibres Organic cotton is generally understood as cotton, from non-genetically-modified plants, that is certified to be grown without the use of any synthetic agricultural chemicals such as fertilizers or pesticides.

The farmers undertake not to use chemicals, and to recycle as much as possible the waste stemming from their activity. Lyocell fibres are produced by regenerating cellulose in an organic solvent, N-methylmorpholine- N-oxide NMMO hydrate. Non-toxic, biodegradable NMMO solvent used is almost completely recycled [17].

The fibre is significantly more sustainable than oil-derived synthetic fibres and natural fibres such as cotton need pesticides and fertilisers to grow. Land required is less in case of the eucalyptus trees, from which lyocell is made [18]. It is produced from carcinogenic benzene Equation 1. Natural glucose can be converted into adipic acid by an enzyme discovered in genetically modified bacteria Equation 2. Polyurethane polymers are presently produced from toxic diisocyanate. A series of polyurethanes based on bis-carbamate diols are synthesised using the Candida antarctica lipase B as catalyst.

The use of biopolymers — plastics made from corn, sugar, starch and other renewable raw materials — has exploded in recent years. The chemical structures of a few biopolymers are shown in Figure 2. Cargill Dow's wonderful and well-known technology uses corn to produce polylactic acid PLA. Due to its high strength, PLA can be fabricated into fibres, films, and rods that are fully biodegradable into lactic acid and carbon dioxide and compostable, since they degrade within 45— 60 days. The several benefits of corn fibres are expected to make these fibres preferable over the currently available natural and man-made fibres.

Henry Ford first used soy plastic to construct various car parts. A new composite materials has been derived from soy flour and flax resin cross-linked with glutaraldehyde, derivable from bio- feedstocks. The textile recycling industry is one of the oldest and most established recycling industries in the world. Textile recycling materials may be pre-consumer or post consumer i.

Polyester fibre is one of the most non-biodegradable polymers which create environmental problems. Major revolution happened in when Wellman Inc.

There are two broad types of recycled polyester namely: 1 Simply melted and re-extruded into fibres and 2 A multi-stage de-polymerisation and re-polymerisation to produce better quality yarn. However, re-cycled polyester yarn is not always as good as virgin polyester. Colour consistency is difficult to achieve, particularly on pale shades [22].

Greener Dye and auxiliaries The greener approaches are: 1 Elimination of harmful azo dyestuffs 2 Alternative synthesis for eco-friendly products. They, in general, have poor to moderate light fastness.

It was found that the natural additives Vitamin C ascorbic acid and gallic acid found in stomach, tea leaves, oak bark and many other plants were most effective in reducing the rate of fading in madder, weld and woad dyed cotton [23].

Efficiency Paramenters Atom Economy: Atom economy atom efficiency describes the conversion efficiency of a chemical process in terms of all atoms involved desired products produced. For the reaction, atom economy should be high i. Conversion: OR Reaction Selectivity: 5.

Environmental Load Factor: It should be minimum. Kelly Martin Dec. I did and I am more than satisfied. ShreeRakshaYadavM May.

Shreya Mutalikdesai Apr. Selcan Hatun Feb. Show More. Total views. You just clipped your first slide! Clipping is a handy way to collect important slides you want to go back to later. Now customize the name of a clipboard to store your clips. Visibility Others can see my Clipboard. Cancel Save. Exclusive 60 day trial to the world's largest digital library. Activate your free 60 day trial. Compared to conventional methods, ultrasonication can bring several benefits such as being environmentally friendly no toxic chemical are used or produced , low cost, and compact, allowing on-site treatment.

Besides an overview. Green Sustainable Process for Chemical and Environmental Engineering and Science: Microbially-Derived Biosurfactants for Improving Sustainability in Industry explores the role biosurfactants may play in providing more sustainable, environmentally benign, and economically efficient solutions for mitigating challenges experienced in the industrial sector. Sections cover an introduction to their production and review. Development in Waste Water Treatment Research and Processes: Innovative Microbe-Based Applications for Removal of Chemicals and Metals in Wastewater Treatment Plants focuses on the exploitation of various biological treatment technologies and their use to treat toxic and hazardous contaminants present in industrial effluent and restore the contaminated sites, a topic.

Many hydrological, geochemical, and biological processes associated with water reclamation and reuse are poorly understood. In particular, the occurrence and effects of trace organic and inorganic contaminants commonly found in reclaimed water necessitates careful analysis and treatment prior to safe reuse. Water Reclamation and Sustainability is a practical guide to. This book discusses new and innovative trends and techniques in the removal of toxic and or refractory pollutants through various environmental biotechnological processes from wastewater, both at the laboratory and industrial scale.

It focuses primarily on environmentally-friendly technologies which respect the principles of sustainable development, including the advanced trends in. Bioremediation by Sanjay K. Natural Water Remediation by James G.

Shah,Jayanta Kumar Biswas.