Adsorption of Pb2+ and Cu2+ ions from aqueous solutions by mango tree (Mangifera indica) saw dust

The removal of heavy metal ions Cu2+ and Pb2+ from aqueous solution using mango tree (Mangifera indica) saw dust as adsorbent under different experimental conditions was investigated. The effects of pH,contact time, temperature, adsorbent dosage and initial metal ion concentrations for the removal of Cu2+ and Pb2+ ions from aqueous solutions were studied using atomic absorption spectrophotometer. The results showed that increasing the amount of adsorbent led to an increase in the percent removal of lead and copper. The optimum pH obtained was pH 6 for copper and pH 8 for lead, with percentage removal of 99.9% Pb2+ ions and 70.1% Cu2+ ions. It was observed that Mangifera indica saw dust removed more of Pb2+ than Cu2+ ion in all the adsorption experiments

Sustainable conversion of agro-wastes into useful adsorbents

Preparation and characterization of raw andactivated carbon derived from three different selectedagricultural wastes: kola nut pod raw and activated (KNPRand KNPA), bean husk raw and activated (BHR and BHA)and coconut husk raw and activated (CHR and CHA) wereinvestigated, respectively. Influences of carbonization andacid activation on the activated carbon were investigatedusing SEM, FTIR, EDX, pHpzcand Boehm titration tech-niques, respectively. Carbonization was done at 350°C for2 h followed by activation with 0.3 M H3PO4(ortho-phosphoric acid). Results obtained from SEM, FTIR, andEDX revealed that, carbonization followed by acid acti-vation had a significant influence on morphology and ele-mental composition of the samples. SEM showed well-developed pores on the surface of the precursors after acidtreatment, FTIR spectra revealed reduction, broadening,disappearance or appearance of new peaks after acid acti-vation. EDX results showed highest percentage of carbonby atom respectively in the order BHA[KNPA[CHArespectively. The pHpzcwas found to be 5.32, 4.57 and 3.69for KNPA, BHA and CHA, respectively. Boehm titrationresult compliments that of pHpzc, indicating that the sur-faces of the prepared adsorbents are predominantly acidic.This study promotes a sustainable innovative use of agro-wastes in the production of cheap and readily availableactivated carbons, thereby ensuring more affordable waterand effluent treatment adsorbents

Sorption kinetic study on the removal of phenol using fluted pumpkin and commercial activated carbon

Batch adsorption experiments were performed to study the removal kinetics of phenol from aqueous solution using activated carbon derived from fluted pumpkin stem waste (FAC) and a commercial activated carbon (CAC). Optimum removal of 98.50% and 98.40% phenol was achieved at the equilibrium time of 60 mins for FAC and CAC respectively. The applicability of three kinetic models, the pseudo first, pseudo second order and Elovich models for the description of the experimental data was examined. The experimental data was most suitably analysed by the pseudo second order model with a high regression coefficients (R2) value for phenol on FAC and CAC as 0.987 and 0.980 respectively. The correlation coefficients followed the order pseudo second order > Elovich kinetic model > pseudo-first order. Fluted pumpkin is the largest consumed vegetable in the West African sub region and therefore, creates one of the major agro waste problems in Nigeria. Preliminary investigations showed that several tons of these waste are produced daily in market places around the country but scarcely useful and therefore create environmental nuisance. The results obtained could be useful for the application of agricultural wastes for phenol removal from industrial wastewater