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An innovative benign process for recovery lactic acid from its fermentation broth is proposed using a novel hyper-cross-linked meso-micropore resin and water as eluent. This work focuses on modeling the competitive adsorption behaviors of glucose, lactic acid and acetic acid ternary mixture and explosion of the adsorption mechanism. The characterization results showed the resin had a large BET surface area and specific pore structure with hydrophobic properties. By analysis of the physicochemical properties of the solutes and the resin, the mechanism of the separation is proposed as hydrophobic effect and size-exclusion. Subsequently three chromatographic models were applied to predict the competitive breakthrough curves of the ternary mixture under different operating conditions. The pore diffusion was the major limiting factor for the adsorption process, which was consistent with the BET results. The novel HD-06 resin can be a good potential adsorbent for the future SMB continuous separation process.

Conventional activated carbon used in decolorization of citric acid fermentation broth has the disadvantage of high citric acid loss. In this study, a novel biomass-based carbon material, namely HBCM, was prepared via H3PO4 activation of hydrothermally treated corncob. The material was fully characterized by SEM, BET, TG, FTIR, XPS and pHpzc. The results showed that the material's SBET was as high as 1720 m2 g−1 and several weak-acid functional groups existed on its surface, which contributed to efficient decolorization with low citric acid loss. By adjusting the solution pH value to around 7, nearly no citric acid was lost. Furthermore, the adsorption behavior of pigments on HBCM was systematically investigated under optimized pH. The results indicated that the adsorption was spontaneous and endothermic. Intra-particle diffusion was the rate-limiting step. By comparing FTIR data before and after adsorption, it was found that oxygen-containing functional groups on the HBCM surface participated in pigment adsorption. Overall, the tailor-made HBCM performed excellently with a 99% decolorization ratio and nearly no citric acid loss under optimum operating conditions. It could be a potential adsorbent in the removal of pigments from citric acid fermentation broth.

In this work nanofiltration technology has been employed for removal of inhibitors and recovery of monosaccharides from dilute acid lignocellulose hydrolysates. The influences of feed solution pH, permeate flux, and Na2SO4 concentration on the rejection of monosaccharides and inhibitors were investigated. The results showed that the pH for the separation of carboxylic acids and furans from monosaccharides should be as low as possible. With increase of Na2SO4 concentration carboxylic acid and furan rejection decreased. Subsequently, the Donnan steric pore and dielectric exclusion model coupled with mass balance was used to predict the rejection of solutes at different permeate fluxes. In order to select a suitable permeate flux and operating time, multi-objective optimization was carried out to obtain the maximum total inhibitor removal efficiency, the maximum monosaccharide recovery rate, and the minimum water consumption. The optimal operating conditions were then verified using the real hydrolysate as feed solutions. More specifically, for the treatment of 6 L of a hydrolysate solution, 13 L of water and a treatment time of 35 min were required. This process allowed the removal of 90% inhibitors, while 93.55% glucose, 90.75% xylose, and 90.53% arabinose were recovered. Finally, a batch column equipped with a strong acid cation exchange resin was employed to recover the monosaccharides from the hydrolysate. Using water as an eluent, 95.37% of the sulfuric acid and 94.87% of the monosaccharides were recovered. In all, we demonstrated that the combination of nanofiltration with electrolyte exclusion chromatography is a promising integrated process for the recovery of monosaccharides and inorganic acids from dilute acid corncob hydrolysates.

A series of porous-carbon adsorbents termed as HDPC (hydrochar-derived pyrolysis char) were prepared from corncob and used for the 1-butanol recovery from aqueous solution. The influences of pyrolysis temperature on properties of the adsorbents were systematically investigated. The results showed that hydrophobicity, surface area, and pore volume of HDPC samples increased with an increase in pyrolysis temperature. Furthermore, the adsorption mechanism of 1-butanol on the adsorbents was explored based on correlation of the samples properties with adsorption parameters extracted from the 1-butanol adsorption isotherms (K F and Q e12 ). Overall, the 1-butanol adsorption capacity increased with a decrease in polarity and an increase in aromaticity, surface area and pore volume of HDPC samples. However, at different pyrolysis temperature, the factors causing the increase of 1-butanol adsorption on the adsorbents are variable. The kinetic experiments revealed that the pores played a vital role in the 1-butonal adsorption process. The intraparticle diffusion model was used to predict the adsorption kinetic process. The simulation results showed that intraparticle diffusion was the main rate-controlling step in the 1-butanol adsorption process.