Natural dyes have been used from ancient times for multiple purposes, most importantly in the field of textile dying. The increasing demand and excessive costs of natural dye extraction engendered the discovery of synthetic dyes from petrochemical compounds. Nowadays, they are dominating the textile market, with nearly 8 × 105 tons produced per year due to their wide range of color pigments and consistent coloration. Textile industries consume huge amounts of water in the dyeing processes, making it hard to treat the enormous quantities of this hazardous wastewater. Thus, they have harmful impacts when discharged in non-treated or partially treated forms in the environment (air, soil, plants and water), causing several human diseases. In the present work we focused on synthetic dyes. We started by studying their classification which depended on the nature of the manufactured fiber (cellulose, protein and synthetic fiber dyes). Then, we mentioned the characteristics of synthetic dyes, however, we focused more on their negative impacts on the ecosystem (soil, plants, water and air) and on humans. Lastly, we discussed the applied physical, chemical and biological strategies solely or in combination for textile dye wastewater treatments. Additionally, we described the newly established nanotechnology which achieves complete discharge decontamination.

https://www.mdpi.com/2076-3417/11/14/6255/pdf

Diversity of Synthetic Dyes from Textile Industries, Discharge Impacts and Treatment Methods

Large-scale membrane technology has been widely implemented and rapidly growing for roughly 40 years. However, considering its entire life cycle, there are aspects being characterized by low sustai...

Toward the Next Generation of Sustainable Membranes from Green Chemistry Principles

With the growth in the global human population, resource availability has become minimal. The creation of technology that is free of toxins for the remediation of the water/wastewater treatment for the sustainable development of global civilization is a matter of urgency. The development of cleaner and greener technologies with significant health and environmental benefits would be greatly influenced by nanotechnology. Nanotechnology technologies are being investigated for their potential to offer ways to remove water pollutants, as well as to increase the efficacy of conventional technologies used in environmental cleanup. Green nanotechnology is a nanotechnology area that envisions sustainability across a number of applications. This paper addresses issues relevant to green nanotechnology for sustainable development. Nanomaterials synthesis and applications have been used to solve water pollution by reducing the cumulative energy consumption during the synthesis or production process, the ability to recycle and manufacture new products and the use of environmentally friendly nanomaterials  in water/wastewater remediation have been reviewed in the current study. Green nanotechnology offers choices to develop the next generation of water treatment systems.

Recent advances in greenly synthesized nanoengineered materials for water/wastewater remediation: an overview

Improved hemostatic effects by Fe3+ modified biomimetic PLLA cotton-like mat via sodium alginate grafted with dopamine

Design strategy of poly(vinylidene fluoride) membranes for water treatment

Completely green and sustainable preparation of PVDF hollow fiber membranes via melt-spinning and stretching method.

Green preparation of polyvinylidene fluoride loose nanofiltration hollow fiber membranes with multilayer structure for treating textile wastewater.

Solvent-free green fabrication of PVDF hollow fiber MF membranes with controlled pore structure via melt-spinning and stretching

Poly(vinylidene fluoride) (PVDF) is one of the most widely used membrane forming polymers with good processability, outstanding mechanical properties, excellent thermal and chemical stability. In this work, PVDF hollow fiber membranes were prepared through the melt spinning method with CaCl2 and PEG as the composite pore forming agents. The influence of different contents of CaCl2 and PEG on the membrane’s structure and properties were studied based on the pore size distribution, porosity, permeation flux, and oil/water separation test etc. There was no obvious dense layer on the PVDF hollow fiber membrane surface, which exhibited multiple pore structure. With the increase of PEG contents, the pore size, the porosity and oil flux improved effectively, correspondingly, the water contact angle and liquid entry pressure decreased. The permeation fluxes of kerosene also increased obviously with the increase of PEG contents, and the maximum flux of M-3 reached as high as 398.4 L·m-2·h-1. Applied to oil/water separation test, M-3 exhibited good oil/water separation performance, and its separation efficiency for water-in-kerosene emulsion can still reach more than 95 % after ten cycles. In particular, there were not any solvents and diluents used in the preparation process, which was a relatively green preparation process. 

Yifei Gao

Papers

Completely green and sustainable preparation of PVDF hollow fiber membranes via melt-spinning and stretching method.

Green preparation of polyvinylidene fluoride loose nanofiltration hollow fiber membranes with multilayer structure for treating textile wastewater.

Solvent-free green fabrication of PVDF hollow fiber MF membranes with controlled pore structure via melt-spinning and stretching

Green preparation of PVDF hollow fiber membranes with multiple pore structure via melt spinning method for oil/water separation