India is a producer of a colossal number of biomasses with high quantity. Even after using them for energy generation, large proportions of residues remain unutilised. They could be utilised as an adsorbent-material to get rid of phenol from aqueous streams. Phenol is listed as highly toxic as per available databases. Thermo-chemical treatment methods have been widely reported to improve the characteristics of biomass-based adsorbents. In this work, based on the availability, three biomasses, Acacia Nilotica Branches (AC), Lantana Camera (LA) and Rice-Husk (RI), were given the treatment. The resulting activated forms of adsorbents were named activated Acacia Nilotica Branches (ACC), activated Lantana Camera (LAC) and activated Rice Husk (RIC). The materials obtained had a high content of fixed carbon, iodine number, BET surface area, and methylene blue adsorption. The operating parameters for sorption in terms of dosage, pH, time of contact, initial phenol concentration and agitation speed were optimised. At these conditions, the adsorption isotherms were compared, and they were explained by Langmuir, Freundlich, and Temkin models. LAC and RIC, respectively highest, followed sorption capacity of ACC. Kinetics of the process on adsorbents considered followed pseudo-first-order and pseudo-second-order models.

India produces an enormous number of biomasses in the form of agricultural and forestry residues. To handle their disposal, they need to be explored as adsorbents, as one of the alternatives for their utilizations. Biomasses, having a high content of carbon, can be used as low-cost adsorptive materials for the removal of phenol from aqueous streams. Ten biomasses, abundantly available in the Sangrur area of Punjab (India), were characterized. Based on their determined characteristics and availability, Acacia nilotica branches (ANB), Lantana camera (LC), and rice husk (RH) were selected for the study. As these biomasses removed low percentages of phenol, they were activated using thermochemical treatment. Their properties as adsorbents improved significantly. When they were subjected to phenol sequestration, the percentage removal of adsorbate was at 97%, 90%, and 83% by activated ANB (ANBC), activated LC (LCC), and activated RH (RHC), respectively. The equilibrium and kinetics of the process of adsorption on these activated biomasses were analyzed mathematically. It was possible to regenerate the spent ANBC, LCC, and RHC in a single step, with 1 M NaOH solution.

Biomasses in the forms of agricultural and forestry residues are gaining attention as alternative sources of energy due to various limitations of conventional sources of energy. Their applications as energy sources should be renewable and eco-friendly. The selection of biomass needs pairing with a suitable thermochemical process for the generation of biofuels and their precursors. This article communicates the investigation of acacia nilotica branch, bagasse, berry branch, coconut coir, corn cob, cotton stalk, groundnut shell, rice husk, rice straw and wheat straw as biomasses, for their considerations to thermochemical transformations. The authors explored the residues for their bulk density, calorific values, proximate analysis, ultimate analysis, ash fusibility characteristics and thermogravimetric analysis. The bulk density and calorific values of materials considered were quite low compared to that of conventional solid fuels. Therefore, they required palletisation for their economical utilisation as feedstocks for thermochemical conversions to energy carriers. The proximate analysis indicated that the fixed carbon:volatile matter of acacia nilotica branch was highest at 0.35, suggesting it as the most preferred feedstock for pyrolysis. The ultimate analysis showed that H/C (molar element ratios) of all residues were near to a constant value indicating the emissions of volatiles/gases were close to same quality after their specific thermochemical transformation. Ash deformation and fusion temperatures of materials lied in the range of 900-1500°C, fixing the operating temperature limits for their transformations through combustors and gasifiers. Thermogravimetric analysis in the N 2 atmosphere indicated that the rate of pyrolysis was highest for all residues, in the temperature range of 300-500°C, suggesting the sufficiency of one reactor to carry out pyrolysis for the individual biomass. Thus, the analysis of biomasses for their thermochemical transformations is the prerequisite for their effective utilisations.

Briquettes produced from agro-residues are fairly good substitute for coal, lignite and firewood. Briquettes from saw dust have high specific density of 1400 kg/m3 compared to bulk density of 210 kg/m3 (approx.) of loose saw dust. Loading/unloading, transportation and storage costs of agro-residues are drastically reduced if they are converted in the form of briquettes. Formation of briquettes at the very site of its production stops air pollution to a large extent. Hence briquetting of saw dust produces renewable and environment friendly source of energy. In this paper an attempt is made to design and fabricate briquetting machine for saw dust on lab scale to produce briquettes at the rate of 7kg/hr.Effect of moisture content in saw dust and binders used have been studied on briquette density, power consumption/kg of briquette produced and calorific value/kg of briquette. Thermal efficiency of chulha (local stove) using prepared briquette was obtained to be 5%.

In the quest for cost-effective production of biodiesel, selection of cheap feedstocks and catalysts play the significant role. Waste cooking oil is abundantly available from all types of restaurants throughout the world. Catalyst selected for this feedstock should be heterogeneous. Coconut coir, which is biomass and source of carbon, was selected for its study as a catalyst for biodiesel production. This paper is based on a comparison of a solid catalyst by two processes: (i) sulphonation of coconut coir char (pyrolysed at 500°C for 3 hours) and (ii) digestion of pyrolysed coconut coir with 10% NaOH at 70°C for 4 hours followed by sulphonation. Comparison of both the solid catalysts thus prepared was done based on their physical properties, total acid density, SEM and FT-IR analysis. The higher percentage of fixed carbon content, higher acid density and BET surface area, better morphological surface and pronounced presence of sulphonic (-SO 3 H), carboxylic (-COOH) and hydroxyl (-OH) groups favours the selection of catalyst prepared by the second method for further study for biodiesel formation using waste cooking oil as the feedstock. Effects of various parameters on biodiesel production: alcohol to oil ratio (A:O), time of reaction, reaction temperature and catalyst loading were studied. At the optimised conditions, the biodiesel conversion was 90.12%. Biodiesel produced by the method was characterised regarding fuel properties and were found close with the standard values.