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Production factory synthetic dyes

International Journal of Environmental Science and Technology. Textile industries are responsible for one of the major environmental pollution problems in the world, because they release undesirable dye effluents. Textile wastewater contains dyes mixed with various contaminants at a variety of ranges. Therefore, environmental legislation commonly obligates textile factories to treat these effluents before discharge into the receiving watercourses.

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Content:

Chemical technology: Dyes

VIDEO ON THE TOPIC: How It's Made - Inorganic Pigments

Log in. This site uses cookies to enhance your user experience. ERROR 1. ERROR 2. Password and Confirm password must match. If you have an ACS member number, please enter it here so we can link this account to your membership. ACS values your privacy. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

Log in here. Already an ACS Member? Choose the membership that is right for you. Discounts will be applied automatically at checkout. Your account has been created successfully, and a confirmation email is on the way. Credit: Intech Digital High-resolution color patterns can be printed directly onto cotton using pigment inks rather than dyes to reduce the use of water and chemicals. They may not know that dyeing clothes requires massive amounts of water, energy, and chemicals.

Those chemicals are released in wastewater from dye houses and textile mills in places such as China, India, and Bangladesh. Reports of rivers with unnatural hues have inspired government crackdowns and sustainability pledges from international apparel brands. Read on to learn about greener ways to color clothes that may soon be available from your favorite retailer.

In early June, Dalton Cheng realized something big was afoot. Cheng, who is head of technology for the textile printing firm Intech Digital, heard from customers that Chinese government authorities in Jiangsu province had shut down massive factories that produce synthetic dyes used by the textile industry. Intech, headquartered in Hong Kong, might be in a position to help apparel industry customers out of a critical supply bind. Printing textiles with pigments rather than dyes uses very little water, Cheng says, and produces much less waste than traditional methods.

Contact us to opt out anytime. Digital printing is one example from a growing list of new, more sustainable fabric-coloring technologies from both major suppliers and smaller chemical and biotech start-ups. But the barriers facing those working to promote a more sustainable textile technology are quite high. Price competition is fierce, and profits are shrinking thanks to volatile raw material costs and rising wages.

The largest impact of the factory shutdowns has been in the supply and price of so-called disperse dyes, which are used to color synthetic fibers like polyester, a specialty of Chinese producers, Schlaefke says. Availability of reactive dyes, which are used on cotton, was also reduced, though manufacturers in cotton-rich India are likely to take up the slack. In India as well, the government is taking steps to reel in the textile industry to save precious water resources. While both cotton and polyester are normally colored with synthetic dyes, dyeing cotton is a more water- and heat-intensive process.

To ensure colorfastness, dyed fabric or yarn is washed over and over again in hot water, creating large amounts of wastewater. All told, about L of water is used to produce 1 kg of fabric. A review of wastewater treatment steps found that textile effluent contains high concentrations of dyes and chemicals, including chromium, arsenic, copper, and zinc.

Dyes and chemicals released into waterways also block sunlight and increase biological oxygen demand J. Process Technol. Bleeding and crocking: Two components of colorfastness. Bleeding happens when dye comes off a fabric in contact with liquid. Crocking occurs when a dye on a dry fabric rubs off on another dry fabric. Colorfastness: The ability of a dye to preserve the original color during industrial processing and subsequent customer use.

Digital textile printing: Directly printing colors and patterns onto fabric using design software, large-format printers, and specialty inks made with pigments or dyes. Digital printing is an alternative to standard screen printing, which uses a constrained color palette and requires separate stencils and production steps for each color.

Dye: Soluble chemicals that contain chromophores, or color-containing compounds. Dyes are mixed with other additives in a color solution. They can be derived from natural sources, such as plants, but are more commonly human made. Different classes of dyes are used for different fibers and stages of the textile production process.

Direct dye: A class of dye that can be applied directly to cotton or other cellulosic fabrics such as rayon, silk, and wool. Direct dyes are applied in a neutral or alkaline bath of hot water. They do not require mordant or fixatives for fastness; instead, they attach with hydrogen bonds and van der Waals forces. Direct dyes are soluble salts of complex sulfonic acids, including diazo or polyazo chemicals. Disperse dye: A category of nonionic dyes used to color synthetic yarns and fabrics such as polyester.

These organic chemicals, mostly monoazo dyes, are nonsoluble and rely on dispersing agents to spread the color molecules in water. Reactive dye: A class of colored synthetic organic chemicals that attach to textile fibers via a chemical reaction that forms a covalent bond.

Reactive dyes are the most permanent of all dye types and are the most common type of dye used on cotton and other cellulose fibers. They are categorized by their functional group, such as dichlorotriazine or vinyl sulfone.

Dye exhaustion or dye fixation: The mass of dye taken up by the yarn or fabric divided by the total initial mass of dye in the water bath. Once the dyeing process reaches equilibrium, a portion of the dye remains in the dye bath and becomes part of the dye process wastewater. The exhaustion ratio depends on the quality of the dye and the characteristics of the fiber. Leveling agent: Used in disperse dyeing to regulate or slow the uptake of dye onto synthetic fibers to ensure that the color level is uniform.

Leveling agents are often nonionic surfactants that increase the solubility of the dye and slow adsorption. Mordant: Also called a dye fixative, a substance used to chemically bond a dye to natural fibers to ensure fastness. Mordant chemicals include alum, caustic soda, and metal salts. The mordant forms a coordination complex with the dye, increasing its molecular weight and making it insoluble.

Pigment: Insoluble materials, usually in powder form, that add color to inks, paints, plastics, cosmetics, and foods. When used on textiles, they require binders or other additives to attach to the fibers. Pigments can be derived from minerals but can also be made synthetically. Because they are not soluble in water, they can last longer than dyes. To reduce this burden, Huntsman has developed a line of dyes for cotton called Avitera that bonds to the fiber more readily. According to the company, the colors require one-quarter to one-third less water and one-third less energy.

Thanks to these extra reactive groups, the dye step lasts about four hours, compared with seven hours for conventional dyes. Still, it takes a lot of legwork to sell customers on a new suite of dyes. Different regions and countries have different cost structures, he says.

Another way to improve the bond between dyes and cotton fibers is a process called cationization. In North Carolina, textile industry veteran Tony Leonard is taking that approach. Leonard is the inventor and technical director behind ColorZen, a start-up that has developed a cotton pretreatment step.

ColorZen treats raw cotton fiber right from the field after the seeds are removed. After treatment, cotton is spun into yarn at customer facilities. It also cuts out almost half the dye compared with processes that call for salts in the dye bath.

The company has a partnership with the manufacturing technology firm Jabil to help it scale up its plant in Mebane, N. It is also in a program run by the apparel start-up incubator Fashion for Good. Hohenstein developed Oeko-Tex, a series of standards and tools for certifying nontoxic textiles. The first version of the standard was called Oeko-Tex for the number of chemicals it tracked. Oeko-Tex certification is now up to more than chemicals. Synthetic indigo, used to make blue jeans blue, is an example of a dye that can release unreacted chemicals downstream of manufacturing.

Indigo is unlike most dyes in that in its unreduced form it is not soluble. So companies like Archroma upgrade it into easier-to-use, prereduced solutions that are more water soluble. The company became concerned after seeing published reports that about metric tons of aniline per year escapes the dyeing process from 70, metric tons of indigo.

Archroma developed a technology for prereducing indigo to prevent aniline from carrying through as a contaminant. Finished textiles colored with the dye contain a nondetectable amount of aniline, whereas competitor dyes can contain up to 2, ppm of the chemical, according to Archroma.

Carnahan acknowledges differing views about how big a problem aniline is in the textile industry. It has a better reputation than the category 1 carcinogenic amines that cleave off of azo dyes and were an early target for elimination by clothing brands.

Of course, in the beginning, indigo came from a plant, not a factory. The very first pair of modern-style blue jeans, made by Levi Strauss, debuted in That was about 25 years before chemists developed the synthetic route to indigo dye—with its unappetizing starting materials of aniline, formaldehyde, and hydrogen cyanide.

The ambition at Stony Creek Colors is to return to those early days. Founder Sarah Bellos says a complete life-cycle review of the production and use of synthetic indigo provides plenty of reasons to look again at indigo from plants. Dyeing : Warm temperature, long process time, requires addition of large amounts of salt and alkali fixatives.

Washing : Long, energy- and water-intensive process using multiple baths, with at least one at boiling temperature. Washing : Shorter process requiring less energy, water, and chemicals than cotton. Uses alkali and chemical reducing agent.

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Natural Science Vol. Color is the main attraction of any fabric. No matter how excellent its constitution, if unsuitably colored it is bound to be a failure as a commercial fabric. Manufacture and use of synthetic dyes for fabric dyeing has therefore become a massive industry today. In fact the art of applying color to fabric has been known to mankind since BC.

These new textile dyeing methods could make fashion more sustainable

Greenwood Publishing Group Amazon. Written for students beginning a formal study of chemistry, this volume encompasses many different topics in and approaches to introductory chemistry. Chapters are devoted to topics such as the atom, elements and the periodic table, bonding, equilibrium and kinetics, solutions, acids and bases, and chemical reactions. Several chapters discuss broad areas of chemistry including organic chemistry, biochemistry, environmental chemistry, and industrial chemistry. Illustrations and diagrams help the student understand chemical structures and reactions, and numerous tables present a wealth of reference information. The historical developments of chemical concepts are traced, and biographical information is provided on key individuals responsible for the development of modern chemistry.

Textile dye wastewater characteristics and constituents of synthetic effluents: a critical review

The last two centuries have been the scene of dramatic change throughout Europe. And one of the main causes of these tremendous and spectacular changes was the economy. These transformations were achieved by people: scientists and political thinkers, inventors and entrepreneurs, educators, skilled and educated workers. Who not only invented machines and computers, but were able to renew economic and political systems. This volume, therefore, presents a new approach to the period by looking at case studies to understand how these changes came about and the impact they had on modern Europe.

In the British chemist William Perkin found the first method to make synthetic dye from coal tar. This started an industrial revolution within the chemical industry.

Элвин медленно пошел вниз, робот парил над. Джезерак и служители остались: то ли они получили такой приказ, то ли решили, что так удобнее наблюдать. А может быть, они попросту не дерзнули приблизиться к главному святилищу Диаспара. В конце спуска тихий голос вновь подсказал Элвину направление, и тот двинулся по проходу между титаническими конструкциями, похожими на дремлющих истуканов.

Еще трижды голос обращался к нему, и, наконец, Элвин понял, что достиг Машина, перед которой он оказался, была меньше, чем большинство ее соседей, но Элвин все равно ощущал себя карликом.

Пять ее сегментов своими плавными горизонтальными линиями напоминали присевшего зверя. Переведя взгляд на робота, Элвин лишь с трудом смог осознать, что оба аппарата - и робот, и компьютер - суть продукты единой эволюции, и даже именуются они одним и тем же термином "машина".

Я хочу сам изучить его; тайны всегда привлекали меня, а в Диаспаре их слишком мало. Кроме того, я думаю, что Судьба может разыграть с нами шутку, по сравнению с которой все мои усилия будут выглядеть очень скромно. В случае, если это действительно произойдет, я хотел бы увериться, что присутствую в самой гуще событий.

Безличный голос отозвался тотчас же: -- Советнику известно, что я не могу комментировать инструкции, данные мне моими создателями. Джизирак принял эту мягкую укоризну и продолжил: -- Какова бы ни была причина, мы не можем оспаривать факты.

Земля ничего об этом не знала и не хотела знать. Земле все это было безразлично. Олвину --. Все в комнате было погружено в темноту -- кроме одной, светящейся изнутри стены, на которой, по мере того как Олвин сражался со своими видениями, то отливали, то снова набирали силу разноцветные волны.

Кое-что на этой рождающейся картине вполне его удовлетворяло -- он к примеру, прямо-таки влюбился в стремительные очертания гор, вздымающихся из моря. В этих изломанных силуэтах жили сила и горделивость. Олвин долго, изучающе смотрел на них, а затем ввел изображение в блок памяти визуализатора, где оно должно было храниться, пока он экспериментирует с остальной частью картины.

И все же что-то ускользало; хотя он никак не мог уразуметь -- что же .

Nov 27, - The dyeing process is an important step in textile manufacturing. During this The synthetic dyes are produced easily, in different colours, and.

Ничего иного он и помыслить себе не. -- Проблема, волнующая тебя, очень стара,-- говаривал Джизирак Олвину. -- Но ты удивишься, узнав, какое множество людей принимает этот мир как нечто само собой разумеющееся -- и до такой степени, что проблема эта никогда не только пе тревожит их, но и в голову-то им не приходит.

Верно, было время -- человечество занимало пространство, бесконечно большее, нежели этот город. Отчасти ты знаком с тем, чем была Земля до той поры, пока не восторжествовала пустыня и не исчезли океаны. Видеозаписи, которые ты так любишь,-- они из самых ранних, какие только есть в нашем распоряжении. Они -- единственные, на которых Земля запечатлена в том виде, в каком она была до появления Пришельцев.

Не могу себе представить, чтобы записи эти оказались известны заметному кругу людей.

А если необходимо, то можно создать заводы, которые дадут планете эту воду. За годы, лежащие впереди, предстояло сделать так. Джизирак знал, что стоит на рубеже двух эпох: он уже повсюду чувствовал убыстряющийся пульс человечества.

Предстояло, конечно, столкнуться с гигантскими проблемами, но Диаспар пойдет на. Переписывание прошлого набело займет многие сотни лет, но, когда оно будет завершено, Человек снова обретет почти все, что оказалось им утрачено.

Пусть эти существа были обмануты - их долгое бдение в конце концов не осталось без вознаграждения. Словно чудом спасли они былые знания, которые иначе были бы утеряны навсегда. Теперь они смогут, наконец, успокоиться, а их символ веры постигнет судьба миллионов остальных религий, некогда мнивших себя вечными.

Откровение это хотя и несколько встревожило Олвина, но в общем-то, не слишком поразило. Когда-то этой способностью обладали и люди и машины, а механизмы в Диаспаре, не изменяющиеся с течением времени, и по сию пору могли воспринимать мысленные приказы своих повелителей, Но вот сами-то жители Диаспара утратили этот дар, который когда-то они разделяли со своими механическими рабами.

-- Я не знаю, что привело вас из вашего мира в наш,-- продолжала Сирэйнис,-- но коль скоро вы искали встречи с живыми существами, ваш поиск завершен. Если не считать Диаспара, то за кольцом наших гор, кроме пустыни, Было странно, что Олвин, который прежде так часто подвергал сомнению общепринятые взгляды, ни на мгновение не усомнился в словах Сирэйнис.

Он снова обратился к экрану монитора, заставил стену города медленно поплыть по нему и начал поиски. Диаспар почти не видел Олвина в последующие несколько недель, хотя всего лишь какая-то горстка людей заметила его отсутствие.

Джизирак, обнаружив, что его ученик, вместо того чтобы бродить в районе границ города, все свое время проводит в Зале Совета, испытал некоторое облегчение, ибо полагал, что уж там-то с Олвином никакой беды не приключится. Эристон и Итания раз-другой навестили его комнату, убедились, что сын отсутствует, и не придали этому значения.

У Джизирака возникло безошибочное впечатление, что робот что-то ищет но вот что именно, он, конечно, и представить себе не. И вдруг с пугающей внезапностью сверкающая крупинка метнулась вверх и замерла в тысяче футов над поверхностью пустыни.

Олвин испустил шумный вздох удовлетворения.

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