No abstract

Treatment of textile dyeing wastewater using existing physio‐chemical and biological methods is challenging and needs an efficient technique to manage toxic and recalcitrant textile dyes in the environment. As the nano iron particles are highly reactive, nontoxic, and cost‐effective, this study demonstrates the potential of nano iron particles in the decolorization of mono azo methyl orange dye and application to decolorize textile dyeing wastewater. The dye was decolorized 98% within 30 min of reaction time and 54% reduction in total organic carbon was observed. The detected intermediates products such as m/z 149, 128, 84, 73, 56, 55 confirm the efficiency of nano iron particles in degrading textile dyes into lower molecular compounds. The dye decolorization pathway and reaction mechanism are proposed. The treatment of real textile dyeing industry wastewater showed 82% dye color removal and reasonable reduction in the quantity of inorganic pollutants such as chlorides, sulfates. Hence,nano iron particles are highly recommended to remediate textile dyeing wastewater effectively. © 2018 American Institute of Chemical Engineers Environ Prog, 38: S366–S376, 2019

The existing knowledge on the reactivity of green iron particles on textile dye and wastewater decolorization is very limited. In this study, the potential of green iron particles synthesized using grape leaves extract on reactive dye (reactive red 195, reactive yellow 145, reactive blue 4 and reactive black 5) decolorization were investigated. 95–98% of decolorization was achieved for all reactive dyes at 1.4–2.0 g/L of green iron. Maximum decolorization was attained at lower dye concentration and showed very little impact on decolorization when pH was increased from 3 to 11. The pseudo first order fit confirms the reaction between iron particles and dye molecules with rate constant 0.317–0.422 and it is followed by adsorption, data fit with pseudo second order model. Hence, not only adsorption but also the reduction process is also involved in the reactive dye decolorization. Benzene, phenyl sodium, 2-chloro-1,3,5-triazine, naphthalene, sodium benzene sulfonate, benzene 1,2 di amine, anthracene-9,10 dione, aniline, phenol, benzene sulfonic acid were the major intermediates detected in dye decolorization and the respective reaction pathway is proposed. Green iron from grape leaves extract demonstrated better performance and it is recognized as the promising cost-effective material for textile wastewater treatment.

Soil and water quality crisis owing to industrialization is massive at present due to the illegal discharge of wastewater to the environment. Textile is one such industry, discharges untreated wastewater into nearby environment and poses major threats worldwide. Similar situation was observed for the last three decades (1980-2013) along Noyyal river in Tiruppur, India. Since 2013, zero liquid discharge (ZLD) has been adopted by the textile industries in Tiruppur to reduce further deterioration of environment. The groundwater from open wells and soil from agricultural land was examined continuously for three years (2015, 2016 and 2017) in order to assess the existing environment status along Noyyal river basin in Tiruppur. The GIS study reveals that 71% of groundwater remains unsuitable for drinking and also 54% are unfit for irrigation use. The findings further reveal that 61% of surface and 20% of subsurface soils are not suitable for agriculture. The detailed investigations established that the open wells located in the downstream of textile industries and near to Orathupalayam reservoir are highly contaminated with organic and inorganic contaminants associated with textile processing activities. The temporal variation of groundwater in these open wells indicated that the dilution by rainwater is very slow. It is also identified that soils near to the contaminated open wells are extremely affected and soil of 15 cm depth is extremely contaminated. Thus, implementation of ZLD somewhat reduced discharge of wastewater into the basin; however the recovery of groundwater to potable quality and soils for agriculture production needs immediate remediation.