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This study aims to describe the conversion of rice straw (RS) as an agricultural plant waste to high-performance cationic flocculant for kaolin clay suspension in wastewater treatment as an alternative to synthetic ones.

This was done by grafting rice straw after pretreatment with acrylamide (Aam) using microwave irradiation technique without using an initiator in an open vessel container for wastewater treatment. Radiation time, monomer and rice straw pulp concentration as well as microwave power were scrutinized to examine their impact on maximizing the graft yield %. Application of the resultant copolymers as flocculants for kaolin clay suspension was willful by studying the foremost influences inducing the flocculation process, for instance, flocculent dose, pH, stirring speed and extent of grafting.

It is seen from the obtained results that both FTIR, SEM, X-Ray diffraction, Thermo gravimetric analysis and Zeta potential confirmed the formation of the cationic amide group onto the graft copolymer chain in comparison with the ungrafted one; the microwave initiation method proved to be a very efficient tool concerning maximizing the graft yield % with no harsh chemicals used for initiating grafting; the flocculation efficiency of the prepared copolymers augmented by increasing the flocculant dose, pH and stirring speed to a maximum value signified at 2.0 g, 6.0 and 75 r/min, respectively, then decreased thereafter while increased by increasing the extent of grafting within the range studied; the flocculant reserved high flocculation efficiency even after five cycles of flocculation/regeneration; preliminary bridging mechanism demonstrating the attraction between the kaolin anionic suspended particles and cationic poly (Aam)-rice straw graft copolymer has been predicted.

The novelty addressed here is undertaken by preparing a very efficient cationic flocculant using rice straw waste with different degrees of grafting for the treatment of wastewater using this kind of microwave irradiation approach as an eco-friendly tool. As far as the authors are aware, no thorough investigation has been done in the literature until now dealing with the above-mentioned preparation process.

The purpose of this study is to undertake surface graft copolymerization of viscose fabric via altering its fibrous properties by using acrylic acid (AA) as a carboxyl-containing monomer and peroxydisulfate (PDS) in presence of ferrous sulfate as a novel redox pair for initiating grafting. The latter process acted as an energy-saving process with respect to the reduction in polymerization temperature and maximizing the graft yield %, in addition to rendering the grafted viscose fabrics dye-able with cationic dye (crystal violet), which has frequently no direct affinity to fix on fabric.

To make graft copolymerization more efficient and economic, the optimum conditions for graft copolymerization were established. The graft yield % was determined as a function of initiator, catalyst and monomer concentrations and the material to liquor ratio, in addition to polymerization time and temperatures. Metrological characterizations via Fourier transform infrared spectroscopy and scanning electron microscopy of topographic morphological surface change have also been established in comparison with the ungrafted samples.

The maximum graft yield of 70.6% is obtained at the following optimum conditions: monomer (150 % based on the weight of fabric), PDS (50 m mole), ferrous sulfate (80 m mole) and sulfuric acid (30 m mole) at 40° C for 1.5 h using a liquor ratio of 30. Remarkably, grafting with AA enabled a multifold upsurge in color strength, with improvements in the fastness properties of cationically dyed grafted viscose fabric measured on the blue scale in comparison with untreated viscose fabric.

The novelty addressed here is undertaken with studying the effect of altering the extent of grafting of poly (AA)-viscose graft copolymers expressed as graft yield % in addition to carboxyl contents on cationic dyeing of viscose fabric for the first time in the literature. Moreover, rendering the viscose fabrics after grafting is dye-able with cationic dye with high brilliance of shades, which has regularly no direct affinity to fix on this type of fabrics.

This paper aims to develop an indigo-dyed denim fabric treated with a nanosilver colloid in the presence of a natural crosslinker of citric acid for possible surgical gown fabrication applications.

A bleached denim fabric was dyed with the sustainable indigo dye followed by silver nanofinishing through citric acid crosslinking under the pad-dry-cure method. The prepared denim samples were analyzed for chemo-physical, textile, dyeing, antibacterial and finish release properties.

The results demonstrated that the comfort and textile characteristics of nanosilver-treated/indigo-dyed cellulosic fabric were affected due to the crosslinking, surface amphiphilicity and air permeability. These properties were, still, in the acceptable range for the fabrication of naturally dyed and antibacterial nanofinished denim gowns.

The dyeing of denim with synthetic dyes may cause harmful effects on the skin and health of the wearer, and the authors present an eco-friendly sustainable approach.

The authors used the fabric substrate, natural indigo dye and reducing/crosslinker agent of citric acid, all being bio-based, in the fabrication of antibacterial dyed fabric for health care garments.