The growing concern over environmental pollution in recent decades has placed increasing focus on research into the development of sustainable processes associated with the removal of contaminants in waters. Water is scarcer than three decades ago, and there is still no satisfactory solution for the removal of pollutants. One element that has gained worldwide prominence is boron. Although it is a nutrient needed in small amounts for human and plant metabolism, higher levels are toxic to most plants and are associated with reproductive problems in humans. The World Health Organization (WHO) suggests a maximum concentration in drinking water of 2.4 mg/L, but many countries have not yet adopted this recommendation in their water treatment controls. At present, there is no general method for boron removal; several techniques can be used, such as electrodialysis, precipitation, chemical coagulation and electrocoagulation, complexation/nanofiltration, phytoremediation, ion exchange, reverse osmosis and adsorption with different materials. The selection of a particular treatment technology should be made not only on the basis of its efficiency but also with consideration of the associated environmental and financial costs. Biopolymers are a potential solution that has received little attention in the literature. Biopolymers and their derivatives are diverse and abundant in nature; they exhibit fascinating properties and are increasingly important in many applications thanks to their environmentally-friendly characteristics. A small number of publications report the possibility of using tannin gel (Morisada et al., 2011), cellulose cotton (Liu et al., 2007) or chitosan modified with N-methy-D-glucamine (Sabarudin et al., 2005), sugars (Morisada et al., 2011) and diols (Oishi and Maehata, 2013; Fortuny et al., 2014). Biosorption is an effective, simple and cost-beneficial method for the removal of contaminants from waters. This thesis focuses on the development of a sorption-based separation process, using biopolymers and composites for boron removal. The work has been carried out at the Department of Chemical Engineering of the Universitat Politècnica de Catalunya (UPC) in the framework of two research projects (Ref.: CTQ2008PPQ-00417/PPQ and CTQ2011PPQ-22412/PPQ) and the FPI fellowship (BES 2009-026847) financed by the Spanish Ministry of Science and Innovation (MICINN). This work is a continuation of research that has been underway at the Department of Chemical Engineering (UPC) for many years, on the development of advanced separation processes for the removal of valuable compounds or contaminants from aqueous solutions. It contributes to the state of the art on boron separation technologies (examples of which include the development of new composites based on the encapsulation of metal hydroxides in biopolymers). Alginate and chitosan were effectively used as sorbents for boron recovery in the current research. Immobilization techniques were implemented using the technology described by Guibal et al., 2010; active materials are trapped in situ and distributed throughout the polymer support, creating a more stable adsorbent than those obtained by the traditional impregnation method, in which the active material is released partially from the pores of the polymer support while successive adsorption-desorption cycles are performed. Three composite materials have been synthesized in order to improve the sorption capacity, the selectivity towards boron species, and the mechanical properties of the raw sorbents: calcium alginate/alumina (C15l), which improves the sorption capacity of alginate in neutral medium; chitosan/nickel(II) hydroxide [chiNi(III)] and chitosan/Iron(III) hydroxide [chiFer(III)], which increase the sorption uptake of chitosan and improve the handling of hydroxides in the adsorption process, and are stable enough to be used in aggressive environments such as seawater without affecting sorption uptake.

Boron is an element distributed widely in environment mainly in the form of boric acid or borate salts. Boron is an element of demand because of its use in many high technology materials. Moreover boron is an essential element for growth of plants, but may also result in toxicity when present in excessive amounts. As the range between a deficient and toxic amount of boron is very narrow, imbalances in boron nutrition are well-known. For the removal of boron from aqueous solutions, various methods exist which are chemical coagulation, adsorption, solvent extraction and ion exchange processes. In this study, an alternative, energy efficient and easily scalable membrane based method, polymer enhanced ultrafiltration (PEUF) was developed for removal of boron from aqueous boron solutions. PEUF process consists of two steps: complexing boron with a water soluble polymer then removing the complex by ultrafiltration. Previously, boron removal from aqueous solutions was studied in a continuous process with a commercial ligand, polyvinyl alcohol (PVA). In our study, three newly developed polymers, which are derivatives of N-methyl-D-glucamine (P1) and iminodipropylene glycol(P2 and P2G) were used as the boron complexing ligand. P1 and P2 are linear polymers, while P2G is cross linked version of P2. The pilot scale system utilized for the PEUF process accommodates a spiral wound cellulose cartridge with 10000 Da molecular weight cutoffs (MWCO). The effects of operating parameters on performance of PEUF were investigated. The experimental parameters studied are metal/polymer ratio (loading) (0.01-1), pH (7-10). Boron analyses of the samples were made by using ICP-AES. Maximum removal (retention) was 90.1 %. The permeate flux remained constant at around 20 L/m2.hr and was not affected by the operating parameters. Decrease in loading caused the retention of boron to increase. Also at high pH values, retentions were relatively higher. Results showed that PEUF could be a successful.

The impending crisis posed by water stress and poor sanitation represents one of greatest human challenges for the 21st century, and membrane technology has emerged as a serious contender to confront the crisis. Yet, whilst there are countless texts on wastewater treatment and on membrane technologies, none address the boron problem and separation processes for boron elimination. Boron Separation Processes fills this gap and provides a unique and single source that highlights the growing and competitive importance of these processes. For the first time, the reader is able to see in one reference work the state-of-the-art research in this rapidly growing field. The book focuses on four main areas: Effect of boron on humans and plants Separation of boron by ion exchange and adsorption processes Separation of boron by membrane processes Simulation and optimization studies for boron separation Provides in one source a state-of-the-art overview of this compelling area Reviews the environmental impact of boron before introducing emerging boron separation processes Includes simulation and optimization studies for boron separation processes Describes boron separation processes applicable to specific sources, such as seawater, geothermal water and wastewater

This book reviews adsorption techniques to clean wastewater, with focus on pollution by dyes and heavy metals. Advanced adsorbents include carbon nanomaterials, biomass, cellulose, polymers, clay, composites and chelating materials.

HYBRIDIZIED TECHNOLOGIES FOR THE TREATMENT OF MINING EFFLUENTS The main goal of this book is to review the principles, development, and performances of hybridized technologies that have been used for the treatment of mine effluents. Recent developments consist of the integration/hybridization of technologies to achieve the effective removal of pollutants from acid mine drainage (AMD) effluents in a stepwise manner such as to ensure that the cost of the process is minimized, and the resulting water is fit for purpose. This book presents eight specialized chapters that provide a state-of-the-art review of the different hybridized technologies that have been developed over the years for the treatment of mine effluent, including AMD. The successful implementation and challenges of these technologies are highlighted to give the reader a perspective on the management of such waste in the mining industry. In this innovative book, readers will be introduced to The limitations of passive and active treatment processes as stand-alone technologies while appraising the functioning and performances of these technologies when combined to address their challenges; The numerous approaches that have been considered over the years for effective combination of these technologies are explored taking into account their successful implementation at large scale as well as the long-term sustainability. Audience This book will be of interest to academic researchers from the fields of environment, chemistry, engineering, mineral processing, hydrometallurgy, geochemistry, and professionals including mining plant operators, environmental managers in the industries, water treatment plants managers and operators, water authorities, government regulatory bodies officers and environmentalists.

Separations of Water Pollutants with Nanotechnology, the latest volume in the Separation Science and Technology series, offers new solutions for remediating water pollution utilizing nanomaterials with separation methods. Current water purification methods are unsuitable, inconvenient or expensive, so there is a need for new and better processes and techniques. Nanomaterials can purify water by removing pollutants such as heavy metals, pathogens, organic compounds, inorganic compounds, pharmaceuticals, and chemicals of emerging concern. These can effectively replace membrane-based methods if the right expertise is developed—this book helps separation scientists do just that. Existing water treatment problems can be solved by applying a nanotechnology-based processes: antimicrobial nanotechnology, zero-valent iron nanoparticles, nanoadsorbents, nano-enhanced membranes, nanometal oxides, and nano photocatalysts. The current literature places emphasis on materials chemistry rather than the separation methods used for water purification. This new volume presents a collection of chapters that deal with remediation based on separation chemistry. Written by leaders in their respective fields from around the world and edited by Satinder Ahuja, a leading expert on water quality improvement Covers the environmental impact of anthropogenic nanoparticles and plant derived bionanomaterials, which are not contained in other books related to nanomaterials for water purification Illustrates key information visually wherever possible throughout the book, e.g. process diagrams in the nanomaterial synthesis and nanomembrane fabrication chapters, electron microscope images, and more