Environmental assessment of a novel ionic-liquid based method for recycling of PVC in composite materials

Waste PVC is scarcely recycled due to its high chlorine content and its use in composite materials, which reduces the applicability of conventional waste treatment methods, including thermal, mechanical and chemical recycling. For this reason, alternative treatment options are being developed to increase the recyclability of waste PVC. This paper focuses on one such option which utilises ionic liquids (ILs) for material separation and dehydrochlorination of PVC contained in composite materials. Taking blisterpacks used as a packaging for medicines as an example of a composite material, the paper presents for the first time the life cycle environmental impacts of this novel PVC recycling method, in comparison with thermal treatment (low-temperature pyrolytic degradation of PVC). Three ILs were considered for the PVC recycling process: trihexyl(tetradecyl)phosphonium chloride, bromide and hexanoate. The results suggested that the impacts of the process using the first two ILs were comparable, while the system with hexanoate-based IL had 7-229 % higher impacts. Compared to the thermal treatment of waste blisterpacks, the IL assisted process had significantly higher impacts (22-819 %) in all 18 categories considered due to the greater heat requirements and the IL losses. Reducing the latter would lower most impacts by 8-41 %, while optimising the energy requirements would reduce the impacts by 10-58 %. Moreover, recovering HCl would increase significantly the environmental sustainability of the process, resulting in net-negative impacts (savings) in most categories. Overall, these improvements would lead to lower or comparable impacts to those of the thermal treatment. The findings of this study will be of interest to the polymer, recycling and related industries, as well as to process developers.

Effect of Ball-Milling Pretreatment of Cellulose on Its Photoreforming for H2 Production

Photoreforming of cellulose is a promising route for sustainable H₂ production. Herein, ball-milling (BM, with varied treatment times of 0.5-24 h) was employed to pretreat microcrystalline cellulose (MCC) to improve its activity in photoreforming over a Pt/TiO₂ catalyst. It was found that BM treatment reduced the particle size, crystallinity index (CrI), and degree of polymerization (DP) of MCC significantly, as well as produced amorphous celluloses (with >2 h treatment time). Amorphous cellulose water-induced recrystallization to cellulose II (as evidenced by X-ray diffraction (XRD) and solid-state NMR analysis) was observed in aqueous media. Findings of the work showed that the BM treatment was a simple and effective pretreatment strategy to improve photoreforming of MCC for H₂ production, mainly due to the decreased particle size and, specifically in aqueous media, the formation of the cellulose II phase from the recrystallization of amorphous cellulose, the extent of which correlates well with the activity in photoreforming.

Ice algal bloom development on the surface of the Greenland Ice Sheet

It is fundamental to understand the development of Zygnematophycean (Streptophyte) micro-algal blooms within Greenland Ice Sheet (GrIS) supraglacial environments, given their potential to significantly impact both physical (melt) and chemical (carbon and nutrient cycling) surface characteristics. Here, we report on a space-for-time assessment of a GrIS ice algal bloom, achieved by sampling an ∼85 km transect spanning the south-western GrIS bare ice zone during the 2016 ablation season. Cell abundances ranged from 0 to 1.6 × 104 cells ml-1, with algal biomass demonstrated to increase in surface ice with time since snow line retreat (R2 = 0.73, P < 0.05). A suite of light harvesting and photo-protective pigments were quantified across transects (chlorophylls, carotenoids and phenols) and shown to increase in concert with algal biomass. Ice algal communities drove net autotrophy of surface ice, with maximal rates of net production averaging 0.52 ± 0.04 mg C l-1 d-1, and a total accumulation of 1.306 Gg C (15.82 ± 8.14 kg C km-2) predicted for the 2016 ablation season across an 8.24 × 104 km2 region of the GrIS. By advancing our understanding of ice algal bloom development, this study marks an important step toward projecting bloom occurrence and impacts into the future.

Exploring the evidence base for Tier 3 weight management interventions for adults: a systematic review

Specialist weight management services provide a treatment option for severe obesity. The objective of the study is to review the characteristics, impact and practice implications of specialist weight management services for adults in the UK. Systematic review: EMBASE, MEDLINE and PsycINFO were searched from January 2005 to March 2016 with supplementary searches. Adults with a body mass index of ≥40 kg m^-2 , or ≥35 kg m^-2 with comorbidity or ≥30 kg m^-2 with type 2 diabetes and any study of multicomponent interventions, in any UK or Ireland setting, delivered by a specialist multidisciplinary team are the inclusion criteria. Fourteen studies in a variety of settings were included: 1 randomized controlled trial, 3 controlled and 10 observational studies. Mean baseline body mass index and age ranged from 40 to 54 kg m^-2 and from 40 to 58 years. The studies were heterogeneous making comparisons of service characteristics difficult. Multidisciplinary team composition and eligibility criteria varied; dropout rates were high (43-62%). Statistically significant reduction in mean body mass index over time ranged from -1.4 to -3.1 kg m^-2 and mean weight changes ranged from -2.2 to -12.4 kg. Completers achieving at least 5% reduction of initial body weight ranged from 32 to 51%. There was evidence for improved outcomes in diabetics. Specialist weight management services can demonstrate clinically significant weight loss and have an important role in supporting adults to manage severe and often complex forms of obesity. This review highlights important variations in provision and strongly indicates the need for further research into effective approaches to support severely obese adults.

In situ investigation of degradation at organometal halide perovskite surfaces by X-ray photoelectron spectroscopy at realistic water vapour pressure

Near-ambient-pressure X-ray photoelectron spectroscopy enables the study of the reaction of in situ-prepared methylammonium lead iodide (MAPI) perovskite at realistic water vapour pressures for the first time.