S. Suganya

Computation of adsorption parameters for the removal of dye from wastewater by microwave assisted sawdust: Theoretical and experimental analysis

In this research, the microwave assistance has been employed for the preparation of novel material from agro/natural bio-waste i.e. sawdust, for the effective removal of methylene blue (MB) dye from aqueous solution. The characterization of the newly prepared microwave assisted sawdust (MASD) material was performed by using FTIR, SEM and XRD analyses. In order to obtain the maximum removal of MB dye from wastewater, the adsorption experimental parameters such as initial dye concentration, contact time, solution pH and adsorbent dosage were optimized by trial and error approach. The obtained experimental results were applied to the different theoretical models to predict the system behaviour. The optimum conditions for the maximum removal MB dye from aqueous solution for an initial MB dye concentration of 25mg/L was calculated as: adsorbent dose of 3g/L, contact time of 90min, solution pH of 7.0 and at the temperature of 30°C. Freundlich and pseudo-second order models was best obeyed with the studied experimental data. Langmuir maximum monolayer adsorption capacity of MASD for MB dye removal was calculated as 58.14mg of MB dye/g of MASD. Adsorption diffusion model stated that the present adsorption system was controlled by intraparticle diffusion model. The obtained results proposed that, novel MASD was considered to be an effective and low-cost adsorbent material for the removal of dye from wastewater.

Treatment of dye wastewater using an ultrasonic aided nanoparticle stacked activated carbon: Kinetic and isotherm modelling

The present work explains the biosorption of malachite green dye from aquatic systems by nano zero valent iron stacked activated carbon (NZVI-AC), which was prepared by dual surface modification strategy. NZVI-AC was characterized by using FTIR, SEM-EDX, XRD and TGA. NZVI-AC exhibited efficient performance in dye biosorption properties. Experimental variables such as time, pH, dye concentration, temperature and biosorbent dosage influenced Langmuir adsorption capacity of 187.3 mg/g. The present biosorption system was best described by pseudo-first order kinetics. The dye was completely knocked out of the solution within 60 min at equilibrium. The thermodynamic behaviour of NZVI-AC was exothermic, feasible and spontaneous. Experimental data was engaged to validate new solid-liquid phase equilibrium model, showing the average absolute relative deviation 7.72%. Hence the procedure was non-toxic, potential to retain biosorbent from the solution, applicable for multiple cycles. In context, NZVI-AC can be recommended for the treatment of dyes from industrial effluent.

Bromate Formation in Drinking Water and Its Control Using Graphene Based Materials

The increasing interest in the use of ozone in drinking water treatment has led to concern over the formation of ozonation by-products. Disinfection with various hypochlorite solution results in the bromate formation which is being carcinogenic tested against laboratory animal. Looking at near future, the bromate concentration level is beyond the limit of provisional water guidelines drawn by the World Health Organization. From the analysis of low dose bromate extrapolation models at an upper 95% confidence limit risk of 1 in 105 of the population, the results are life threatening. Possible control options originate from ‘design-for-purpose’ to control bromate formation or reduction scientifically. In this chapter, the potential grapheme based materials in creating next-generation and ground-breaking solutions to the water challenges of our times have been discussed. It is believed that grapheme based materials can meet water challenges in a sustainable ways.

Evaluation of Next-Generation Sequencing Technologies for Environmental Monitoring in Wastewater Abatement

The waste generation and disposal into natural water bodies become a serious topic to be concerned by researchers today. Consequently, there is a demand for new strategies and technologies to address wastewater treatment and subsequent recycle and reuse especially in arid/semiarid areas. The harmful microbial load in raw sewage, toxic chemicals, and nutrients may cause pollution and can render water utilities unfit for human consumption or recreational activities. Biological treatment process is advantageous and constitutes tools to biodegrade organic matter, transfer toxic compounds into harmless products, and remove nutrient in wastewater microbiology. Bio-monitoring employs sentinel or indicator species in water bodies to infer water quality, ecosystem health status, and to protect public health from waterborne risks. Next-Generation Sequencing is one of the most leveraging studies focus on the ecology of microbial-mediated processes that influence freshwater quality such as algal blooms, contaminant biodegradation, and pathogen dissemination. Sequencing methods targeting small subunit (SSU) rRNA hypervariable regions have allowed for identification of microbial species which serve as bioindicators for sewage contamination in raw, treated, semi-treated water utilities. In addition, hidden diversity of unknown or uncultured microorganisms reveals the genetic capabilities for biodegradation of toxins and other contaminants. This chapter aims to provide brief knowledge about the development of bioindicators for sewage pollution and microbial source tracking, characterizing the distribution of toxin and antibiotic resistance genes in water samples. The assessment of biological risk, suitability, and unfairness inherent in the application of Next-Generation Sequencing may be a prior concern.

Laser-Based Apparel Production

LASER (Light Amplification by Stimulated Emission of Radiation) technology is being largely used in apparel industry for cutting, patterning garments, designer neckties, and denim fading with 3D body scanning and engraving leather since nineteenth century. Laser cut design tends to be reserved for haute couture designs and reduced low cost, flexibility, and anti-counterfeiting to produce apparel in ready-to-wear collections. Laser light is a form of electromagnetic radiation used to cleave various materials with high accuracy in cutting, sealing fabric edges in order to prevent fraying. The change in energy states within the atoms of certain materials leads to produce light by laser. And that has few basic characteristics, namely intensity, coherency, monochromaticity, and collimation. These are helpful to distinguish laser light from natural light. Generally, laser beams are narrow, travel in parallel lines, but do not spread out or diverge as light from most normal sources. Therefore, using laser cuts without any pressure on the fabric is meant for no extra energy requirement other than laser. It tends to no unintended marks left on the fabric especially in silk and lace. Adopting high-energy laser cuts material by melting, burning, or vaporizing it. Most significantly, laser beam decomposes dye, resulting in producing vapors followed by venting them away from garment. This is how denim fading works. While scanning the universal barcodes to identify products such as apparels, fashion accessories, the following lasers are used such as CO2 laser, neodymium (Nd) laser, and neodymium yttrium-aluminum-garnet (Nd-YAG) lasers. They use precise concentrated beam of light. CO2 laser is a gas laser, producing an infrared light to absorb by organic material. Solid-state lasers such as Nd and Nd-YAG lasers, on the other hand, rely on a crystal to create light beam. Yet, it is hard to reproduce in an exact way. Hence, laser cut makes each ideal task to create an identical design; many countries are unaware of this technology. But the laser cut clothes are shell out for a lot of cash. However, safety issues and gases used in laser apparels must be replenished to meet multi-fiber agreement regime to make textile products more safe, clean, and competitive. This chapter focuses on laser technology in the apparel production and their potential hazards in health-related concerns.

Toxic Free Supply Chain for Textiles and Clothing

The existing structure of supply chain of textile industry is complex at every level that it leads for inter-dependencies across a network starting from raw material to manufacturing, clothes reaching customers. Complexity contributes to variability and uncertainty where a change in one element can have an effect on other elements. To feature such cumulative and combinatorial effect throughout the supply chain, good practice in labour standards leading to a legal minimal wage and realistic living wage, working hours, safety and integrated infrastructure have to be monitored by government bodies. The intention of this article is to serve idea on risk reduction measures for hazardous substances at every level through supply chain by identifying the toxic substances and its hazardous properties. For example, substantial shares of silver, triclosan, triclocarbon are released after the biocide treatment of textile from laundering. To avoid such human risk, the REACH registration is a source of limited knowledge on risk assessment of many substances used in textiles. Indian Garment Industry finds that inventory management, visibility, lead time, collaboration with private and government sector, technology as risk factors all over the supply chain. Based on target customer groups and scale size on production, most of the private companies are facing appropriate supply chain strategy for product offerings. The use of safer chemicals in the entire life cycle and production in apparel brings a substitution plan for hazardous chemicals. The aim of this chapter is to assure the use of safer chemicals and their substitution in acceptable range in the whole production procedures of textile products. That should meet customers demand for a cleaner production with no or less pollution in order to protect environment, new or modified environmental policies and regulations in order to protect workers and consumers health. Other regulative measures to aware customers by labeling toxic free clothes and suitable method for the pre-determination of toxicity in research laboratories must be taken into consideration by textile manufacturers.

Introduction to sustainable fibres and textiles

Abstract After agriculture, the textile sector is the oldest and dates back several centuries ago. In terms of trade, gross domestic product, and the overall Index of Industrial Production, the garment industry grows 5.4% every year, according to the Cotton Textiles Export Promotion Council. Hot and humid weather, locally available labour, raw cotton, the generation of hydropower, entrepreneurial skills and port facilities and transport systems are favourable to the textile industry and create a great demand for the production of yarn. Meanwhile, problems exist in the textile industry owing to disorganized systems and infrastructure, the global recession, strong competition in the world market, a lack of energy and electricity and diminishing export orders. A rise in the price of raw materials resulted in lower productivity, advanced machinery and modernization, bringing down the value of textile products. The textile industry is also responsible for a major part of the total industrial pollution that affects farmland and rivers. To overcome these demands and environmental impacts, organic farming helps in the cultivation of highly drought-tolerant crops. They are grown to be eco-friendly, for waste-to-wear technology. The processing and supply chain is also concerned about the long-term health of the planet, by reducing the release of CO 2 into the environment. This chapter discusses the upgrading of technology that results in a less concentrated feed, no or a less harmful effect on the environment and traceability and transparency in the product, which guarantees minimum standards with regard to sustainability.