Higher contact angles or amplified wettability observed on surfaces of rough solid materials are typically expressed as a function of a physical dimension (roughness factor). Herein, we present a simple experimental approach that demonstrates that roughness may only magnify the inherent surface chemistry that seems to have direct influence on surface wettability. We investigate gradual change in surface chemistry (hydrophobisation) of rough and smooth glass surfaces, from a very low concentration (10−7 M) of dichlorodimethylsilane, DCDMS through various intermediate hydrophilic/hydrophobic states to when the surfaces are maximally hydrophobised with DCDMS at 0.1 M. The wettability of the modified glasses was studied by water contact angle measurements using drop shape analysis system (DSA). The data obtained indicate a deviation from Wenzel model, with the functionalized rough glass surfaces showing higher reactivity towards DCDMS when compared to the smooth glass surfaces, indicating that the two surfaces are not chemically identical. Our study reveals that just like transforming a solid material to powder, a well-divided glass (rough) surface may not only exhibit a greater surface area than the smooth counterpart as rightly predicted by the Wenzel model, but seems to be bloated with functional groups (–OH or –CH3) that can amplify surface interaction when such functional species dominate the solid surface.

This study evaluates the physico-chemical parameters and heavy metals in water, sediments and Tympanotonus fuscatus obtained from three sample sites along Iko River in Eastern Obolo LGA, AkwaIbom State. The heavy metal analysis results on Pb, Cd and Ni in sediments and Tympanotonus fuscatus were used to estimate the human health and ecological risk assessment of the study area. The human health risk assessment tools utilized in this study were estimated dietary intake (EDI), total hazard quotient (THQ) and hazard index (HI) while sediment pollution parameters evaluated were contamination factor (CF), contamination degree (CD), pollution load index (PLI) and geoaccumulation index (Igeo). Results obtained showed that EDI of Cd in periwinkle in the study sites ranged from 0.2 – 6.4 µg/kg-bw/day and exceeded the provisional tolerable dietary intake (PTDI), while EDI for Pb (0.0004 – 2.6 µg/kg-bw/day) and Ni (0.32 – 2 µg/kg-bw/day) was within the limit for all sites, except Ni in site II (34 µg/kg-bw/day) which was higher than the PTDI of 5 µg/kg-bw/day. The THQ of Cd in all sites was greater than 1, while Pb and Ni generally recorded THQ < 1. The hazard index (HI) was as follows: site I (2.36), sites II (24.44) and site III (6.5), highlighting a potential hazardous effect to humans as a result of the consumption of Tympanotonus fuscatus obtained from site II and III. The sediment pollution assessment revealed that the contamination factor (CF) and geoaccumulation index, Igeo of Cd were far above the permissible limits while Pb and Ni were mostly within limits. The estimated contamination degree (CD) and pollution load index (PLI) showed a high degree of pollution, which can be mainly attributed to the high degree of Cd contamination in the sediment. Therefore, the area under investigation is highly polluted and the periwinkle obtained from Iko river in the study area is unfit for human consumption.

This study was carried out to assess indoor air quality (IAQ) in schools in Akwa Ibom State of Nigeria during the rainy (June-July) and dry (November-December) seasons of 2018. IAQ parameters were examined to assess pollutant levels in schools within Akwa Ibom State in single setting only (naturally ventilated classrooms). Schools were randomly selected from two zones: zone 1 which is located within the Capital City (Uyo metropolis) and represents the 'urban sector', and zone 2 which is located within the southern part of the state in close proximity to the oil and gas industrial region and represents the 'industrial sector'. Indoor air investigation included the following parameters: particulate matter (PM 1 , PM 2 , PM 5 , and PM 10), carbon monoxide (CO), carbon dioxide (CO 2) levels, temperature and relative humidity, which were simultaneously measured in fourteen (14) sampling days using Fluke 985 Particle Counter and Fluke 975 AirMeter. Multiple statistically analysis techniques were used to compare IAQ parameters and test for significant differences between the zones (urban vs. industrial) and annual seasonal variations. The concentrations of particulate matter (PM) in the naturally ventilated classroom in industrial zone during the rainy season ranged from 5152-5984 μg/m 3 for PM 1 ; 2744-3207 μg/m 3 for PM 2 ; 137-149 μg/m 3 for PM 5 ; 38-46 μg/m 3 for PM 10 and in urban zone, the concentrations of PM ranged from 1978-2491 μg/m 3 for PM 1 ; 1010-1311 μg/m 3 for PM 2 ; 38-56 μg/m 3 for PM 5 ; 15-24 μg/m 3 for PM 10. During the dry season, the concentrations of PM in the naturally ventilated classroom in industrial zone ranged from 6138-6999 μg/m 3 for PM 1 ; 2984-3980 μg/m 3 for PM 2 ; 146-159 μg/m 3 for PM 5 ; 47-59 μg/m 3 for PM 10 and in urban zone, the concentrations of PM ranged from 2556-3972 μg/m 3 for PM 1 ; 1911-2311 μg/m 3 for PM 2 ; 51-66 μg/m 3 for PM 5 ; 18-34 μg/m 3 for PM 10. Results of this study has revealed that the concentrations of PM 1 , PM 2 , PM 5 , and PM 10 measured in the naturally ventilated classroom in industrial zone were significantly (p < 0.001) higher than those measured in the urban zone during both rainy and dry seasons. In this present study, the concentrations of PM 10 measured were found to be much lower than the ambient maximum contaminant level for airborne PM 10 standard promulgated by the United States Environmental Protection Agency (US-EPA) (150 μg/m 3 daily average and 50 μg/m 3 annual average) and World Health Organization (WHO) PM 10 guidelines values (50 μg/m 3 daily average and 20 μg/m 3 annual average). Apart from re-suspension of atmospheric particles, anthropogenic activities in industrial zone significantly influenced the measured concentrations of PM compared to those measured in urban zone. In addition, the lower concentration of CO and CO 2 measured indicated adequate air exchange at the time of the assessment in the naturally ventilated classrooms during the sampling period. The results obtained reveal important contributions towards understanding o...

The photocatalytic reduction of Cu (II), Pb (II), Cd (II) and Cr (VI) ions in aqueous solution has been investigated. The photocatalyst utilized was nano titanium dioxide, composed of 80% anatase and 20% rutile; the UV light source was a 15 W UV bulb with a wavelength of 254 nm. The results obtained indicated a reduction efficiency order as follows; Cr Original Research Article

Physicochemical properties of artisanal refined gasoline (ARG) and regular automotive gasoline (RAG) sampled from the Eastern Obolo Creek and Mkpat Enin, Akwa Ibom State, Nigeria were investigated. This was to compare the physicochemical properties of the two gasoline samples with each other and their compliance with American Society for Testing and Materials (ASTM) standards. The finding revealed an antiknock index of RAG (91.15%) and ARG (83.05%), atmospheric distillation of RAG (185°C) and ARG (184°C), Reid vapor pressure of RAG (0.53 kg/cm 3 ) and ARG (0.36 kg/cm 3 ), gravity of RAG (0.771) and ARG (0.683), sulfur content of RAG (0.014%/wt) and ARG (0.02%/wt), while Flash point for RAG were Pensky Martens −25°C, Abel-Pensky −33°C and ARG Pensky Martens −27°C, Abel-Pensky −35.36°C, respectively. The research octane number, motor octane number, Reid vapor pressure, sulfur content, and specific gravity of RAG were (ASTM) compliant while only the final boiling point and sulfur content of ARG were within ASTM range. Based on the findings, the LRG might have been poorly refined or adulterated and could constitute problems in automotive engines if used. However, this crude technology can be upgraded and the gasoline quality improved through alkylation, isomerization, and cyclization. Artisanal refiners should be trained to become proficient with the intent of becoming incorporated into the upstream petroleum sector.