In this study, versatile boron-doped graphitic carbon nitride (gCN) incorporated mesoporous SBA-15 (BGS) composite materials were prepared by thermal polycondensation method using boric acid & melamine as a B-gCN source material and SBA-15 as mesoporous support. The prepared BGS composites are utilized sustainably using solar light as the energy source for the continuous flow of photodegradation of tetracycline (TC) antibiotics. This work highlights that the photocatalysts preparation was carried out with an eco-friendly strategy, solvent-free and without additional reagents. To alter the amount of boron quantity (0.124 g, 0.248 g, and 0.49 g) have to prepare three different composites using a similar procedure, the obtained composites viz., BGS-1, BGS-2 and BGS-3, respectively. The physicochemical property of the prepared composites was investigated by X-ray diffractometry, Fourier-transform infrared spectroscopy, Raman, Diffraction reflectance spectra, Photoluminescence, Brunauer-Emmett-Teller and transmission electron microscopy (TEM). The results shows that 0.24 g boron loaded BGS composites degrade TC up to 93.74%, which is much higher than the rest of the catalyst. The addition of mesoporous SBA-15 incresed the specific surface area of the g-CN, and heteroatom of boron increased the interplanar stracking distance of g-CN, enlarged the optical absorption range, reducing the energy bandgap and enhanced the photocatalytic activity of TC. Additionally, the stability and recycling efficiency of the representative photocatalysts viz., BGS-2 was observed to be good even at the fifth cycle. The photocatalytic process using the BGS composites demonstrated to be capable candidate for the removal of tetracycline biowaste from aquesous media.

Liquid hot water (LHW) pretreatment conditions were optimized from various severities using response surface methodology to convert water lettuce (WL; Pistia stratiotes) to fermentable sugars to enhance the enzymatic digestibility of pretreated WL. The LHW pretreatment was performed using a 2% (w/v) WL loading over a temperature range of 152–208 °C and pretreatment times of 9–51 min. The optimal conditions for the LHW pretreatment were determined to be 190.7 °C for 51 min [a severity factor (log R0) of 4.38], which gave the highest total reducing sugar yield (17.26 g/L) and a high removal level of hemicellulose (68.32%) in the subsequent cellulase digestion. The physical structure of WL after pretreatment revealed changes to the WL structure that increased its susceptibility to attack by enzymes; an increased crystallinity, surface area, and total pore volume together with a lower hemicellulose and lignin content compared to the untreated WL.

The combination of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate with either water or dimethyl sulfoxide (DMSO) as a co-solvent was applied for the pretreatment of Napier grass under microwave irradiation at 150 °C for 1 h in order to enhance the subsequent cellulase enzymatic hydrolysis of the cellulose to sugars via increased enzyme accessibility. The influence of the IL/water and IL/DMSO (at different IL/DMSO (v/v) ratios) pretreatment on the structural changes of the Napier grass was examined using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analyses. The transformation of cellulose I in the IL/DMSO pretreated Napier grass was clearly observed. The results indicated that cellulose structural changes occurred and a higher yield of fermentable sugars was obtained from the subsequent enzymatic hydrolysis for the pretreated Napier grass samples with a high crystallinity index.