Utilization of Annona senegalensis as a Sorbent for THE Removal of Crude Oil from Aqueous Media

In the present study, the efficiency of Annona senegalensis fiber to remove crude oil from aqueous solution was evaluated. The crude Annona senegalensis (CAS), retted Annona senegalensis (RAS) and bleach Annona senegalensis (PFAS) were subjected to sorption studies to optimize their sorption capacity. The results revealed that the efficiency of sorbent to remove crude oil from water is related to the sorbent weight, contact time, initial oil concentration and temperature of sorption. It was found out that increase in sorbent weight led to increase in sorption capacity from 3.99-5.25g/g, 5.51-7.12g/g, and 5.01-6.72g/g in CAS, RAS and PFAS respectively. Increased in Initial oil concentration also increased the oil sorption capacity by 20-21% until it reach equilibrium. Sorption time was varied from 10, 20, 30, 40, 50, 60 and 70 minutes and the highest sorption capacity was recorded at 30 minutes before a gradual decreased was observed. Sorption capacity decreased with increased in temperature above 400C. The sorbent exhibited good reusability after 8 cycles, with less than 50 % reduction in sorption capacity. The kinetics of crude oil sorption onto CAS, RAS and PFAS follow the second- order model with correlation coefficients higher than 0.99. The results obtained revealed that crude oil adsorption onto the Annona senegalensis fiber can be used as an effective adsorbent to oil spill cleanup in water bodies.

Removal of Crude Oil from Aqueous Medium by Sorption on Sterculis setigera

This study will present a novel method for crude oil remediation in water. The research was carried out to explore the possible application of Sterculia setigera as a potential biodegradable sorbent for oil cleanup from water. The crude Sterculia setigera (CSS), retted Sterculia setigera (RSS) and bleached Sterculia setigera (PFSS) were subjected to sorption studies to optimize their sorption capacity. The results revealed that the efficiency of sorbent to remove crude oil from water is related to the sorbent weight, contact time, initial oil concentration and temperature of sorption. It was found that increase in sorbent weight led to increase in sorption capacity from 3.75 -5.12 g/g, 4.72- 6.41 g/g, and 4.61-6.18 g/g in CSS, RSS and PFSS respectively. Oil sorption capacity increases by 21-27% when oil concentration was varied from 5-20 g. Contact time played a role only at the beginning of oil sorption study and became less important near equilibrium. Sorption time was varied from 10-70 min and the highest sorption capacity was recorded at 30 min. then it gradually reduced and became steady. The effect of temperature was investigated from 30-60°C. A decreased of 34-37% in oil sorption capacity was observed with increased in temperature. RSS exhibit lower water sorption when compared to the other sorbents. The sorbents showed good reusability after 8 cycles, with less than 50% reduction in sorption capacity and good reusability. Sterculia setigera demonstrated good potentials for utilization as natural sorbent for oil cleanup.

Adsorption of Hydrogen Sulphide by Commercialized Rice Husk Biochar (RHB) & Hydrogel Biochar Composite (RH-HBC)

Hydrogen sulfide (H2S) is a naturally occurring component found during microbial disintegration and processing of natural gas & oil which can cause wellbeing and condition issue if being discharged into a climate at high fixation. Activated carbon which cost a lot in manufacturing is used as an adsorbent for removing these hazardous gases. As an alternative, the abundance waste of biomass available can be converted into good use. Biochar is one of the most practical and promising adsorbents that shows incredible potential as an adsorbent for the expulsion of contaminants in wastewater and gas treatment. This study covered on the characteristics and adsorption performance of two adsorbents Activated Rice Husk Biochar (RHB) and Rice Husk Hydrogel Composite (RH-HBC) on hydrogen sulfide. RHB is prepared by treating grinded rice husk biochar using aqueous Zinc Chloride (ZnCl2 ) and hydrochloric acid (HCl) solution to increase the size of pores of active sites and remove the impurities present in on the adsorbents. Polymerization is conducted by using initiator (ammonium persulfate, APS), monomer (acrylamide, AAm) and crosslinker (N,N'-methylenebisacrylamide,MBA) to create treated hydrogel biochar (RH-HBC). The adsorption performance is done to evaluate the effect of sorbent weight (20 g, 25 g, 30 g), H2S gas flow rate (200 L/hr, 150 L/hr, 100 L/hr) and temperature (30℃, 50℃, 70℃). RHB shows better porosity compared to RH-HBC where it has a higher surface area (222.85m2/g) compared to RH-HBC (8.68m2/g). While the presence of alkene group C=C in RH-HBC gives more stability to withstand high temperature compared to RHB. From the result, it can be concluded that the increased the sorbent weight, give an increased in adsorption capacity. When increased the gas flow rate, it gives a shorter contact time between gas and adsorbent which result in less adsorption capacity. RH-HBC give longest breakthrough time and highest adsorption capacity compared with RHB in all experiment.

Removal of Pb2+ ions from aqueous solution by P(HEA/IA) hydrogels

A series of poly(2-hydroxyethyl acrylate-co-itaconic acid), P(HEA/IA), hydrogels with different HEA/IA ratio, were synthesized using free radical crosslinking/copolymerization and investigated as sorbents for Pb2+ ions from aqueous solutions. Hydrogels were characterized using DMA, FTIR, DSC, SEM and AFM. The adsorption was found to be highly dependent on hydrogel composition, solution pH, sorbent weight, ionic strength and contact time. Five isotherm models, Langmuir, Freundlich, Redlich-Peterson, Temkin and Dubinin-Radushkevich, were applied to the sorption data. The best fit was obtained with Redlich-Peterson isotherm. The separation factor, RL, value indicated favorable sorption for Pb2+ ions. The maximum sorption capacities were 392.2 and 409.8 mg/g for P(HEA/2IA) and P(HEA/10IA), respectively. Kinetic data showed best fit with pseudo-second-order model. Thermodynamic studies revealed that the reaction was exothermic and proceeds with a decrease in entropy. Moreover, P(HEA/IA) hydrogel showed the most pronounced sorption toward Pb2+ ions from environment containing Cu2+, Zn2+, Cd2+, Ni2+ and Co2+ ions. Sorption/desorption experiments, showed that the P(HEA/IA) hydrogels could be reused without significant loss of the initial properties even after three adsorption-desorption cycles.