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© 2017 The Author(s). Background: Pretreatment is necessary to reduce biomass recalcitrance and enhance the efficiency of enzymatic saccharification for biofuel production. Ionic liquid (IL) pretreatment has gained a significant interest as a pretreatment process that can reduce cellulose crystallinity and remove lignin, key factors that govern enzyme accessibility. There are several challenges that need to be addressed for IL pretreatment to become viable for commercialization, including IL cost and recyclability. In addition, it is unclear whether ILs can maintain process performance when utilizing low-cost, low-quality biomass feedstocks such as the paper fraction of municipal solid waste (MSW), which are readily available in high quantities. One approach to potentially reduce IL cost is to use a blend of ILs at different concentrations in aqueous mixtures. Herein, we describe 14 IL-water systems with mixtures of 1-ethyl-3-ethylimidazolium acetate ([C2C1Im][OAc]), 1-butyl-3-ethylimidazolium acetate ([C4C1Im][OAc]), and water that were used to pretreat MSW blended with agave bagasse (AGB). The detailed analysis of IL recycling in terms of sugar yields of pretreated biomass and IL stability was examined. Results: Both biomass types (AGB and MSW) were efficiently disrupted by IL pretreatment. The pretreatment efficiency of [C2C1Im][OAc] and [C4C1Im][OAc] decreased when mixed with water above 40%. The AGB/MSW (1:1) blend demonstrated a glucan conversion of 94.1 and 83.0% using IL systems with ∼10 and ∼40% water content, respectively. Chemical structures of fresh ILs and recycle ILs presented strong similarities observed by FTIR and1H-NMR spectroscopy. The glucan and xylan hydrolysis yields obtained from recycled IL exhibited a slight decrease in pretreatment efficiency (less than 10% in terms of hydrolysis yields compared to that of fresh IL), and a decrease in cellulose crystallinity was observed. Conclusions: Our results demonstrated that mixing ILs such as [C2C1Im][OAc] and [C4C1Im][OAc] and blending the paper fraction of MSW with agricultural residues, such as AGB, may contribute to lower the production costs while maintaining high sugar yields. Recycled IL-water mixtures provided comparable results to that of fresh ILs. Both of these results offer the potential of reducing the production costs of sugars and biofuels at biorefineries as compared to more conventional IL conversion technologies. Graphical abstract Schematic of ionic liquid (IL) pretreatment of agave bagasse (AB) and paper-rich fraction of municipal solid waste (MSW).

Additional file 1. FTIR spectra of untreated and pretreated biomass under different ionic liquid–water systems. Unt: untreated, AGB: agave bagasse, MSW: municipal solid waste, Blend: agave bagasse/municipal solid waste (1:1) blend. FTIR spectra of all untreated and pretreated samples from agave bagasse, municipal solid waste and the agave bagasse/municipal solid waste (1:1) blend between 800 and 2000 cm−1 with a spectral resolution of 4 cm−1.

Adolescence is a critical developmental period in the life course and a time when most young people enter into their first intimate relationships. The significance of a young person’s early intimate relationships are two-fold: firstly they can impact upon a young person’s development, depending upon the nature and quality of the relationship; secondly, they provide a framework for intimate relationships in adulthood. Exploration of behaviours young people think are acceptable and unacceptable within intimate relationships, including experiences and attitudes towards violence in these relationships, has been relatively limited within the UK. Drawing upon feminist criminology and feminist qualitative psychology, this thesis explores young people’s experiences and views of teenage intimate partner violence, with a focus on how young people understand, interpret and make sense of this violence. This research is a mixed methods study. A quantitative online survey was completed by 233 young people aged 16-19 and a series of eight predominantly single gender qualitative focus groups were held with young people aged 16-19. The study addresses a significant gap in the research literature. Firstly, it provides insights into the nature and dynamics of different forms of violence in older adolescents’ intimate relationships. Secondly, it provides a nuanced understanding of what intimate partner violence means to different groups of young people. Thirdly, it outlines what participants perceive young people could or should do if they are in a violent relationship in a five stage model which includes perceived barriers and enablers to recognising and doing something about experiences of partner violence. The perspectives and experiences of the young people in this research illuminate how best to respond to this problem.

Additional file 2. Chemical changes tracked of fresh and recycled [C2C1Im][OAc] (up) and [C4C1Im][OAc] (down). FTIR spectra of recycled ionic liquids [C2C1Im][OAc] and [C4C1Im][OAc] from three different cycles.

Additional file 3. XRD spectrum and crystallinity index (CrI) of agave bagasse under different conditions (untreated, Fresh IL pretreated and IL-recycled). XRD diffractograms of untreated and pretreated agave bagasse under different process conditions.

Additional file 2. Chemical changes tracked of fresh and recycled [C2C1Im][OAc] (up) and [C4C1Im][OAc] (down). FTIR spectra of recycled ionic liquids [C2C1Im][OAc] and [C4C1Im][OAc] from three different cycles.

Additional file 3. XRD spectrum and crystallinity index (CrI) of agave bagasse under different conditions (untreated, Fresh IL pretreated and IL-recycled). XRD diffractograms of untreated and pretreated agave bagasse under different process conditions.