Background: Recently, concerns have been raised regarding the environmental and public health safety of azo dyes, the most widely used synthetic dyes. The membrane technique has been introduced as one of the efficient methods for dye removal treatments. Polyvinylidene fluoride (PVDF) membrane manipulated by surfactants was studied for removal of the azo dye, carmoisine. Methods: PVDF membrane was prepared via non-solvent-induced phase separation (NIPS) and used to remove the azo dye, carmoisine. Three nonionic surfactants including Tween 20, Tween 60, and Tween 80 were used individually as additives in casting solutions to improve PVDF membrane properties. Results: Fourier-transform infrared spectroscopy (FTIR) demonstrated the presence of functional groups of carbonyl (C=O) and hydroxyl (OH), assigned to Tween molecules, in the membrane chemical structure. All Tween species caused a decrease in the surface hydrophobicity of PVDF membranes illustrated by the reduced contact angles. Each Tween at a 2% concentration in the dope solution led to an increase in the pore-size of PVDF membranes, which was estimated by scanning electron microscopy (SEM). However, this impact was reversed at Tween concentrations of 4%. Membranes were assessed for dye removal efficiency and permeate flux in a cross-flow system. Permeability of PVDF membranes improved (~78%) with adding Tween 80 at a concentration of 2%. Tween 60 at a 2% concentration resulted in a ~45% increase in dye removal efficiency of PVDF membranes. And, atomic force microscopy (AFM) showed that Tween 60 increased membrane surface roughness. Conclusion: Surfactant-mediated changes in the surface properties of PVDF membrane improved dye removal efficacy.

There has been much attention to GIS as a tool for gathering, displaying, examining, evaluating, and interpreting data for knowledge discovery in geographical data. The book "Spatial Mathematics: Theory and Practice through Mapping" by Sandra Lach Arlinghaus and Joseph J. Kerski [1] introduces GIS as a tool for introducing mathematical concepts for GIS, visualization, and mapping.The book is mainly an attempt to introduce fundamental spatial concepts in applied way. It supplies plenty of materials and exercises from diverse academic disciplines such as geography, mathematics, physics, and general social science. The inclusion of "spatial mathematics" in the title is somewhat misleading, as the role of mathematics is not always clearly defined. The book mainly focuses on fundamental spatial concepts, rather than addressing advanced mathematical concepts. Thus, it is best-suited for introducing mathematical concepts employed in spatial information science and mapping.Using QR (quick response) codes is the most interesting and innovative part of this book. QR codes facilitate access to relevant materials that support the theoretical concepts. The book contains 10 chapters covering a diverse range of topics pertaining to spatial information science, with each chapter is organized in two distinct parts: theory and practice.According to the content, the book can be divided into two main parts. The first part involves topics related to measurement and geodetic characteristics of the Earth, explained in chapters 1, 2, and 9. Chapters 1 and 2 support a basic understanding of the geometry of the Earth, including topics such as geodetic models, positioning, coordinate systems, and location measurements. Further discussions of the numerical characterization of location on the Earth's surface are terminated in chapter 2, but taken up again in chapter 9. Chapter 9 deals with various map projections and their characteristics, which has an important role in selecting the best projection for displaying maps.The second part of book focuses primarily on spatial visualization techniques, in helping to reveal meaningful structure in the distributions of phenomena in space. Thus, chapters 3 to 8 deal with fundamental analytical techniques in GIS to uncover hidden spatial patterns.