Synthesis and Characterisation of Activated Carbon Obtained from Marula (Sclerocarya birrea) Nutshell

Globally, a ninth of people use polluted water sources because an estimated 300–400 Mt of waste and 90% of sewage are discharged into water bodies from industries and developing countries, respectively. The utilisation of indigenous fruit pits in producing novel adsorbents will greatly benefit in wastewater treatment. In most underdeveloped countries, activated carbon (AC) is imported at a high cost. The study was aimed at synthesising and characterisation of AC obtained from Marula nutshell. Carbonization of organic matter from Marula nutshell was carried out at 200°C, 400°C, 500°C, and 600°C. Sulphuric (H2SO4) and phosphoric (H3PO4) acids were used as activating agents at concentrations of 20–60% ( v / v ). Physicochemical characteristics of the AC, such as bulk density, moisture, ash, pH, and iodine number, were analyzed using standard methods. Functional groups and total carbon content were determined using the FTIR spectroscopy and Nitrogen Carbon Sulphur (NCS) analyzer, respectively. The values of carbon yield and total carbon in activated samples with H2SO4 and H3PO4 were 32.2–93.2%, 26.9–95.8%, and 46–79%, 20.8–69.8%, respectively. The pH, ash, moisture, and bulk density of activated high carbon samples with H2SO4 ranged from 2.4–6.1, 0.65–3.49%, 1.3–8.4%, and 0.42–0.62 gcm−3, respectively. Activated high carbon samples with H3PO4 had 2.7–3.2, 11.3–29.8%, 4.7–14.6%, and 0.39–0.54 gcm−3 pH, ash, moisture, and bulk density, respectively. The synthesised AC samples with 40% H3PO4 at 500°C had the highest iodine value of 1075.7 mg/g. FTIR results showed the presence of aliphatic carboxylic acid salt, inorganic nitrate (NO3−), and phosphate groups in the synthesised AC and were not significantly different ( p < 0.05 ) from commercial AC. The untreated Marula nutshell had some aliphatic hydrocarbon (alkanes), inorganic phosphate ( PO 4 3 − ), aliphatic ester (–COO), and aliphatic carboxylic acid salt (–C(=O)O–) groups. A novel adsorbent, AC was produced from Marula nutshell with the potential to be used in water treatment.

Phytochemical analysis of methanolic extract of Ulva rigida C.Ag. collected from Koothankuzhi Coast, Tirunelveli district, Tamil Nadu, India

The present study was concentrated to explore the phytochemicals present in the methanolic extract of Ulva rigida C.Ag., collected from Koothankuzhi in the south east coast of Tamil Nadu, India. The phytochemical analysis of methanolic extract was screened using the standard procedure for UV-Visible spectroscopic, HPLC and FTIR. The UV-Visible spectrum showed the compounds separated at the nm of 662, 603, 533 and 400 with the absorption 0.653, 0.331, 0.458 and 2.684 respectively. The qualitative HPLC fingerprint profile displayed fourteen compounds at different retention time of 1.770min, 2.230min, 2.540min, 2.870min, 3.090min, 3.377min, 3.900min, 4.257min, 4.797min, 5.340min, 5.853min, 6.520min, 7.730min and 9.220min. The result of FTIR analysis was found the presence of functional groups such as alkynes, sulfonic acids, carboxylic acids, carboxylic acid salt, aldehydes, aliphatic and unsaturated hydrocarbons. Keywords: Ulva rigida, UV-Visible, HPLC, FTIR

Synthesis and Properties of Cross-Linkable Waterborne Polyurethane/HMMM-CNT Nanocomposite

A series of cross-linked waterborne polyurethane/hexamethoxymethylmel-amine-carbon nanotube nanocomposites (WBPU/HMMM-CNT) were synthesized using carboxylic group functionalized CNT. The carboxylic groups on CNT were reacted with the methoxy groups of HMMM to get bonded HMMM-CNT. Unreacted methoxy group of HMMM-CNT was crosslinked with the carboxylic acid salt groups of WBPU and made crosslinked WBPU/HMMM-CNT nanocomposite. The mechanical properties (tensile strength and Young’s modulus) of conventional WBPU, crosslinked WBPU/HMMM, WBPU/CNT and WBPU/HMMM-CNT nanocomposites were compared under three conditions: untreated, wet and dried. It was observed that the mechanical properties of the crosslinked WBPU/HMMM-CNT nanocomposites were the least affected by water compared to conventional WBPU, crosslinked WBPU/HMMM, and WBPU/CNT nanocomposites. Differential scanning calorimetry (DSC) analysis also confirmed that the WBPU/HMMM-CNT nanocomposite can absorbed least water which can be easily removed by heating without destroying their crystalline structure. Crosslinked WBPU/HMMM-CNT nanocomposite recovered most of its mechanical properties of (with optimum HMMM-CNT content) after drying.