Enhanced adsorption of metal ions onto Vetiveria zizanioides biochar via batch and fixed bed studies.

The study highlights the potential of Vetiveria Zizanioides derived biochar for heavy metal removal in multicomponent systems. Biochar efficiency varies with pH, metal ion concentration and residence time. Maximum removal efficiency was found to be 66.34, 67.23, 46.54, 69.92, 68.23 and 63.34% for Arsenic, Copper, Nickel, Cadmium, Lead and Chromium at 90 min respectively. Ternary system revealed that Copper ions have inhibitory effect on Lead ions and have lower adsorption capacity than binary system. Multicomponent isotherm model was used to analyse simultaneous adsorption of metal ions and shows a good fit with modified Langmuir model for binary and ternary systems. Fixed-bed column was tested for scale-up feasibility and maximum adsorption capacity of 139, 130, and 123 mg/g for Lead, Copper, and Nickel ions were obtained at 1.5 L/h and a bed height of 12 cm. In fixed bed column, multicomponent sequence provides more protection against premature exhaustion of biochar.

Simultaneous pretreatment and hydrolysis of hardwood biomass species catalyzed by combination of modified activated carbon and ionic liquid in biphasic system.

The study highlights one pot conversion of hardwood biomass into Total reducing sugars (TRS) and 5-Hydroxymethyl Furfural (5-HMF). Synergistic effect of dilute H2SO4 and ionic liquid in a reaction time of 60 min at 120 °C was examined. Hydrolysis of Catalpa (Catalpa Bignonioides), Indian Rosewood (Dalbergia Sissoo), Chinaberry (Melia Azedarach) and Babool (Acacia Nilotica) catalyzed by modified activated carbon leads to significant product yield. Maximum yield was obtained using Catalpa wood i.e. 92.67% TRS and 70.36% 5-HMF under optimized conditions. Biomass before and after pretreatment subjected to FT-IR, XRD and compositional analysis determined the structural changes. Further, the effect of electrolytes namely; AlCl3, MgCl2, NaCl and KCl were evaluated. Results revealed that using optimized concentration of each electrolyte promoted the conversion to 96.56% (TRS) and 86.23% (5-HMF) using AlCl3 (4 wt%) for Catalpa wood. Addition of DMSO with optimized electrolyte concentration improves the partition coefficient (3.3) and yield to 88.29% (5-HMF).

Synergistic effect of modified activated carbon and ionic liquid in the conversion of microcrystalline cellulose to 5-Hydroxymethyl Furfural.

This study highlights cellulose conversion for the production of 5-Hydroxymethyl Furfural using synergistic effect of modified activated carbon and ionic liquid under moderate reaction conditions. Modified Activated carbon after acid treatment (ACS, ACP, ACH) were used to examine their catalytic activity on hydrolysis of cellulose in [Bmim]Cl medium. Changes in physical-chemical properties were characterized using XRD, FE-SEM, EDX, FT-IR and BET surface area analyser techniques. Modified activated carbon is found competent in enhancing cellulose conversion to Total Reducing Sugars and 5-Hydroxymethyl Furfural. Further, the effect of six metal ions i.e Cr+3, Fe+3, Cu+2, Zn+2, K+ and Al+3 impregnated on sulfuric acid treated activated carbon (ACS) was explored. The catalytic performance improves with the impregnation of metals in the decreasing order: Cr+3> Fe+3> Cu+2> Zn+2> Al+3> K+. These modified catalysts with ionic liquid as solvent are found promising to generate eco-friendly system and cost effective cellulose conversion to value added products.