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The paper and pulp industry stands out to be one of the industries that are growing at a fast pace. Besides their characteristics such as high water consumption of 695.7 million m3 per year and subsequent high energy consumption, there are plenty of environmental impacts arising from this industry. Approximately 300 different types of harmful organic pollutants such as phenols, dioxins, and other organic substances are the significant effluents of the paper and pulp industry. As per the regulations set by the world health organization (WHO), the permissible limit of such pollutants is less than 1 ppm. Since the complete degradation of these pollutants is difficult to achieve using conventional techniques, advanced oxidation processes (AOPs) are widely being used as promising alternatives. On the other hand, depleting non-renewable energy resources are forcing industries to look for energy-efficient technologies. Photocatalysis is one such AOPs, which has the potential to solve the energy-wastewater nexus and is the primary focus of this review in terms of waste treatment from the paper and pulp industry. The photocatalytic materials induce photoreactions by receiving photon energy from light. However, harnessing light energy to the fullest is a challenge owing to the limited share of UV spectrum in sunlight. Different composite photocatalysts at different loadings, pollutant concentrations, and contact time along with their respective efficiencies are reported. The enhancement in thermodynamic driving force due to shift in Fermi energy levels with a suitable example is explained. The dependence of photocatalysis on various factors such as organic species, temperature, and light intensity makes it tough to predict the precise kinetic model in real-life experiments. The hydrogen production from the degradation of organic pollutants was discussed vividly and by optimization of the processes, an estimated amount of 0.45% of the total world's energy could be produced from the paper and pulp industry alone. [ABSTRACT FROM AUTHOR]

Paper waste is a raw material for a lot of products with different added value. The engineering, economic and environmental aspects of paper waste recycling are analysed for production of composite material, cellulose nanofibers and nanocrystals, bricks with paper components, porous carbon, film of biopolymer, enzymatic sugar and bioenergy: bioethanol, hydrogen and biofuel. Through multicriteria analysis, it was possible to determine the most feasible paper waste recycling product in case of four product groups: egg packaging boxes, cardboard, reused paper, cellulose nanomaterials (nanofibers and nanocrystals). The production of cellulose nanofibres and cellulose nanocrystals has an advantage over egg packaging and cardboard production as well as reusable paper.

Paper, in addition to its frequent usage in writing, packaging, printing, etc., has gained comprehensive utility as a flexible and conductive base in sensors, solar energy harvesting, conversion, and storage applications. This is due to its strategic-aiding aspect in terms of environmental friendliness, cost-effectiveness, recyclability, thin, flexible and lightweight nature, biocompatibility, etc., required to develop next-generation flexible devices. The signs of progress in paper-based devices are seen in matured technologies of the paper-based sensor for varied sectors. Also, there have been wide-ranging research efforts on developing paper-based high-performance energy harvesting, conversion, and storage solutions. However, it is a newly emerging area and needs a fundamental and state-of-the-art understanding for future devices development. Thus, the current review summarizes the research progress in this field utilizing paper, understanding fundamental properties w.r.t application, performance enhancement w.r.t material advancements (i.e. paper modification), and technological trends, which is otherwise not yet reviewed earlier. It further sheds light upon the perspectives for their associated and allied technological developments in the energy sector. [Display omitted] • Role of paper properties in energy related applications are discussed. • Paper based electrodes for energy harvesting and conversion devices. • Utilty of papers in energy storage i.e. supercapacitors and batteries is presented. • Challenges and perspectives of realization of paper based devices for energy sector are projected. [ABSTRACT FROM AUTHOR]

Abstract: A simple anaerobic biodegradation process using wastewater treatment plant (WWTP) effluent, shredded paper, and a purge of nitrogen gas was used to produce hydrogen and simultaneously capture nitrogen and phosphorus. Two reactor configurations, a sequencing batch reactor (SBR) and a classic batch reactor (CBR) were tested as simultaneous saccharification and fermentation reactors (enzymatic hydrolysis and fermentation in one tank). The CBR demonstrated greater stability of hydrogen production and simplicity of operation, while the SBR provided better nitrogen and phosphorus removal efficiencies. Nuclear magnetic resonance analyses showed acetic acid to be the main product from both reactors. Optimal CBR conditions were found to be pH 5, 4 g/L loading, 0.45 ml/g Accellerase 1500, and 38 °C. Experiments with an argon purge in place of nitrogen and with ammonium chloride spiking suggested that hydrogenase and nitrogenase enzymes contributed similarly to hydrogen production in the cultures. Analysis of a single fermentation showed that hydrogen production occurred relatively early in the course of TOC removal, and that follow-on treatments might extract more energy from the products. [Copyright &y& Elsevier]