Corrosion inhibition characteristics of two biomass derived extracts from outer leaves of Brassica oleracea (BO) and Citrus paradise mesocarps (CPM) on pipeline steel were investigated using modified gravimetric method at ambient temperature (28 ± ˚C). Petroleum pipeline water was used to simulate a pseudo-anaerobic corrosion cell. The result obtained showed that corrosion was a continuous process in the closed system, while BO and CPM showed near equivalence corrosion inhibition efficiency of 91.45% and 89.44% respectively at the concentrations studied. The thermodynamic data suggests inhibition to be through molecular adsorption on metal surface.

Cashew nut shell liquid (CNSL) extract obtained using soxhlet extraction method with acetone as solvent has been used in the synthesis of Co (II) and Zn (II) metal complexes. The CNSL gave a molecular peak ion of 298g/mol-1 on a GC-MS, an indication that cardanol was more prominent than anacardic acid in the obtained extract. Physicochemical parameters such as saponification value (50.30 mgKOH/g), moisture content (5.10), iodine value (241.00 mgKOH/g), ash content (1.30) and pH (6.31) were equally obtained. The metal complexes of Co (II) and Zn (II) prepared with unmodified (UMCNSL) and aniline modified CNSL (AMCNSL) were characterized using UV-visible, FTIR, melting point and electrical conductivity. Some characteristic FTIR bands were observed for AMCNSL, UMCNCL, AMCNSL-ZnCl2.H2O (1612cm-1) and AMCNSL-CoCl2.6H2O (1612cm-1). The presence of C=N were confirmed in the metal complex of AMCNSL-ZnCl.H2O and AMCNSL-CoCl.6H2O but were not present in the UMCNSL-ZnCl.H2O and UMCNSL-CoCl.6H2O.