![]() These toxic solvent vapors are released throughout the printing manufacturing areas and cause skin and eye irritations to factory operators. Moreover, according to US Environmental Protection Agency (EPA), every textile printing line of the textile mills emits annually an average VOC (volatile organic compound) of approximately 14.3 tons for roller and 32 tons for flat and rotary screens. These toxic chemicals pollute water sources when they are drained, often untreated. For instance, after each printing, approximately 1.5 gallons of printing paste remains in the printing screen, and equipment that must be cleaned with solvents (such as toluene, xylene, and methanol) which uses a great amount of water and electricity. 0.26 million liters of water to dye 8,000 kg of fabric every day this means each kilogram of fabric consumes about 30–50 L of water.Īpart from dyeing, traditional textile printing methods contain many non-eco-friendly aspects. Presently, the textile mills conduct approximately 3,600 types of textile dyeing procedures using over 8,000 chemicals. Additionally, dyeing consumes the largest amount of water in garment manufacturing processes. Over 40 % of dyeing colorants include a carcinogenic material-bound chlorine, and mordants (color fixer), such as chromium. About 2,000–3,000 ppm of salt concentrations are found in most cotton fabric production wastewater that significantly exceeds the federal limit of 230 ppm.ĭyeing processes necessitate the use of multiple toxic chemicals (e.g., heavy metals, pigments, ammonia, and alkali salts). Despite these benefits, the textile mercerization creates negative environmental impacts because of the use of high concentration of sodium hydroxide (NaOH). To bestow fabrics with multiple benefits like enhanced luster, improved moisture absorption (by 7.5–8.5 %), wet resistance, lint reduction, and dyeing methods capable of creating brighter and deeper colors cellulosic fibers (e.g., cotton, hemp, and linen) can be mercerized after weaving. Figure 1: Characteristics of Wastewater from Different Wet Processes The textile industry is responsible for about 17–20% of industrial water pollution. Water is used to rinse or remove unwanted chemicals out of the fabric and as a chemical carrier to the fiber. Textile wet processing industries are completely relying on fresh, soft water for pretreatment, coloration and finishing of textiles. According to physical characteristics, textile waste can be classified into two main groups, which are wastewater and solid waste.Ĭharacterization of Wet Processing Wastewater This enlargement is leaving pollution footprints and potential environmental problems and hazards in each step of textile life cycle. The global textile and apparel market is expected to grow at a compound average annual growth rate of 3.7% and to exceed 100 million tons by 2025. The textile industry is one of the largest industries in the world. Dumping the solid wastes is extremely risky and its thoughtless disposal can cause serious land and air pollution which can be detrimental to human health and environment. Because of these, the chemical-intensive textile and clothing industry which is already among the most polluting industries, has been gaining critical concerns regarding the disposal of textile wastes around the globe. Also, the fast fashion trends have led to overconsumption. Then the finished product can be pumped to the finished product tank and sent to the warehouse.Increasing global population and elevated living standards have resulted in more demand and consumption of textiles to fulfill one of the basic human needs. The solution is pumped to the filter press for filtering to get the clarified liquid product. The sodium silicate solution is obtainedafter the reaction of the materials under high temperature and pressure. ![]() Quartz sand and liquid caustic soda are mixed evenly in the batching tank, and then put the materials into the reaction kettle and filled with steam. lt can produce sodium silicate with molar ratio below 2.5.Īccording to customer needs, we can provide consulting, design, supply, installation, debugging and training services for a complete set of wet process sodium silicate production lines with an output of more than 5000 tons/year. This production method has significant advantages such as low investment, simple process, easy operation, environmental protectionand no waste generation. The wet process of sodium silicate is a production method in which liquid caustic soda and quartz sand are reacted at high temperature and high pressure to obtain sodium silicate.
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