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The CaCCO process (Park et al., 2010), a sugar platform for herbaceous lignocellulosics, was modified and evaluated for fermentable-sugar recovery in solution, using rice straw (RS) as well as stems and leaves of Erianthus arundinaceus (ER), one of the strategic energy crops in Japan. Continuous wet milling of a mixture of feedstock, water and Ca(OH)2, with a weight ratio of 3/7/0.3, was adopted, not only to evaluate the applicability for wet feedstocks, but also for simultaneous Ca(OH)2 mixing with the milled feedstocks. We also applied low temperatures of 95 100 C for the alkali pretreatment to save energy. Enzymatic-saccharification tests were performed for the pretreatment slurries from 10 kg feedstocks for 72 h at 40 C under a CO2-pressurized atmosphere at 0.9 MPa with high-solid loadings of 28.4% (w/w) for RS and 27.8% (w/w) for ER. These tests successfully solubilized 80.6% (RS) and 68.1% (ER) of the total glucose-and xylose residues in the solids. Following centrifugation, the solubilized-sugar concentrations in the recovered solutions were 16.9% (w/v) for RS and 15.5% (w/v) for ER. Thus, we demonstrated that the CaCCO process could be a simple and flexible platform for preparation of dense sugar solutions from dry-and wet feedstocks, which could stimulate a new agricultural bio-industry for vitalizing rural areas.

Effective recovery of dyes and salts from textile wastewater by nanofiltration (NF) remains a serious challenge due to the high consumption of water and energy caused by the limited performance of the available membranes. Herein, a novel strategy is described to prepare loose polyester NF membranes by using renewable quercetin as the aqueous monomer for fractionation of high salinity textile wastewater with minimal water and energy consumption. Compared with NF270, taken as the reference membrane, the QE-0.2/TMC-0.2 membrane significantly improved the efficiency for dye/salt fractionation by 288%. The water consumption was also decreased by 42.9%. The efficiency is attributed to an ultrahigh water permeance of 198 ± 2.1 L −1 m −2 h −1 bar −1 with a high selectivity of 123 (extremely low NaCl rejection of 1.6% and high Congo red rejection of 99.2%). The optimal quercetin-based membrane had an ultrathin separation layer of about 39 ± 1.2 nm with good hydrophilicity and negative charge density. Moreover, this work includes a novel method of comparison with a theoretically ideal membrane, which shows that both the energy and water consumption are near their theoretical minimum. This strategy is expected to save energy and minimize carbon emissions for membrane-based wastewater treatment systems.

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