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21Phosphorous has long been the target of much research, but in recent years the focus has 22shifted from being limited only to reducing its detrimental environmental impact, to also looking 23 at how it is linked to the global food security. Therefore, the interest in finding novel techniques 24 for phosphorous recovery, as well as improving existing techniques, has increased. In this study 25we apply a hybrid simulation approach of molecular dynamics and quantum mechanics to 26 investigate the binding modes of phosphate anions by a small intrinsically disordered peptide. 27Our results confirm that the conformational ensemble of the peptide is significantly changed, or 28 stabilized, by the binding of phosphate anions and that binding does not take place purely as a 29 result of a stable P-loop binding nest, but rather that multiple binding modes may be involved. 30Such small synthetic peptides capable of binding phosphate could be the starting point of new 31 novel technological approaches towards phosphorus recovery, and they represent an excellent 32 model system for investigating the nature and dynamics of functional de novo designed 33 intrinsically disordered proteins. 34 2 Introduction 35 Phosphorous (P) is an essential element in terms of sustaining the world's current and 36 future food supply, for which there is no substitute. [1][2][3] Given that the current P supply is based on 37 the gradual depletion of limited fossil reserves, an increasing demand for P necessitates a change 38 towards more sustainable practices where P is recovered from the large waste streams. The 39 lifetime of remaining high quality phosphate rocks is still being debated, estimates varying from a 40 few decades to a few hundred years. 3,4 There is however a general consensus that P is becoming 41 more and more difficult to access, costs are increasing, more waste is being produced, and the 42 3 global demand is expected to increase. 4,5 Meanwhile, only a fraction of the mined P makes it into 43 the intended plants and animals which humans consume, while most is lost along the way causing 44 serious environmental problems e.g. by eutrophication of lakes, reservoirs, estuaries, and parts of 45 the ocean. 2,4,6,7 46The topic of P has been a point of interest for waste-water treatment engineers for 47 decades. 8 The main attention has however so far been focused almost exclusively on reducing 48 eutrophication, so while many of the now common techniques for P treatment, e.g. chemical 49 precipitation 8 and enhanced biological phosphorus removal 9 (EBPR), are highly efficient for the 50 job they were designed for, they are not necessarily effective in terms of recovering P from its 51 large waste flows, which have different characteristics from the commonly treated domestic 52 wastewater flows and are not always easily intercepted (e.g. erosion and runoff 2 ). One of the 53 current main technologies, optimized for P removal but also applicable to recovery to some 54 extent, is EBPR, where polyphosphate accumulating ...

In forward osmosis (FO), an osmotic pressure gradient generated across a semi-permeable membrane is used to generate water transport from a dilute feed solution into a concentrated draw solution. This principle has shown great promise in the areas of water purification, wastewater treatment, seawater desalination and power generation. To ease optimization and increase understanding of membrane systems, it is desirable to have a comprehensive model that allows for easy investigation of all the major parameters in the separation process. Here we present experimental validation of a computational fluid dynamics (CFD) model developed to simulate FO experiments with asymmetric membranes. Simulations are compared with experimental results obtained from using two distinctly different complex three-dimensional membrane chambers. It is found that the CFD model accurately describes the solute separation process and water permeation through membranes under various flow conditions. It is furthermore demonstrated how the CFD model can be used to optimize membrane geometry in such as way as to promote the mass transfer.

A technique for determining the materialspecific morphology of a polymer−fullerene blend is presented. This technique is applied to solution processed bulk-heterojunction organic solar cells with different weight ratios of polymer−fullerene blend using the PTB7:PCBM material system. Optical and electrical characterizations show that the light absorption increases for larger polymer (PTB7) content, while the fill factor of the fabricated solar cells is improved for larger fullerene (PCBM) content. The materialspecific morphologies of polymer−fullerene bulk-heterojunctions are measured by employing AFM phase imaging. The measured AFM phase images reveal that fullerene material forms flake-like clusters which are embedded in the polymer network. The size of the flakes is increasing with larger content of fullerene material. By correlating the optical and electrical properties with the measured bulk-heterojunction morphologies, the relation between bulk-heterojunction structure and solar cell performances is discussed.

Phosphorus is a ubiquitous element of the cell, which is found throughout numerous key molecules related to cell structure, energy and information storage and transfer, and a diverse array of other cellular functions. In this work, we adopt an approach often used for characterizing metal binding and selectivity of metalloproteins in terms of interactions in a first shell (direct residue interactions with the metal) and a second shell (residue interactions with first shell residues) and use it to characterize binding of phosphorus compounds. Similar analyses of binding have previously been limited to individual structures that bind to phosphate groups; here, we investigate a total of 8307 structures obtained from the RCSB Protein Data Bank (PDB). An analysis of the binding site amino acid propensities reveals very characteristic first shell residue distributions, which are found to be influenced by the characteristics of the phosphorus compound and by the presence of cobound cations. The second shell, which supports the coordinating residues in the first shell, is found to consist mainly of protein backbone groups. Our results show how the second shell residue distribution is dictated mainly by the first shell of the binding site, especially by cobound cations and that the main function of the second shell is to stabilize the first shell residues.