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Water contamination with dyes is harmful to humans and the environment. This study investigated the photocatalytic activity of natural clay (GOL) mixed with carbon nanotubes (CNT) for removal of brilliant black (BB) in wastewater. The materials were characterized with FESEM-EDS, XRD, XRF, FTIR and UV-vis DRS. The natural clay contains 2.34 % TiO2 which is 75% more than most natural clays. SEM showed that CNT were well dispersed and mixed with clay. DRS spectra showed two absorption bands above 380 nm. CNT in GOL has decreased significantly the energy band gaps from 2.75 and 3.25 eV to 1.53 and 2.90 eV for GOL and 10% CNT–GOL, respectively. Photocatalytic activity was enhanced with degradation of BB increased from 66 to 95% with GOL and 10% CNT–GOL respectively after 45 min of visible light irradiation. The improvement can be attributed to the synergy of the interface heterojunction of clay and CNT. The presence of CNT reduces the e− and h+ (e− / h+) pairs recombination and facilitates the production of reactive oxygen species responsible for the decay of dye. The addition of H2O2 to the experiment (2 mmoL) confirmed the role of holes and hydroxyl radicals. Eighty-five percent of BB carbon content was removed with 10% CNT–GOL suggesting that mineralization occurred. After 45 min of visible light irradiation, the degradation kinetic studies followed a second-order reaction with a R2 = 0.997. Therefore, natural clay–CNT nanocomposites can be applied to treat dyes containing wastewaters.

We review the risk of norovirus (NoV) infection to the human population from consumption of contaminated shellfish. From a UK perspective, risk is apportioned for different vectors of NoV infection within the population. NoV spreads mainly by person-to-person contact or via unsanitary food handling. NoV also enters the coastal zone via wastewater discharges resulting in contamination of shellfish waters. Typically, NoV persists in the marine environment for several days, with its presence strongly linked to human population density, wastewater discharge rate, and efficacy of wastewater treatment. Shellfish bioaccumulate NoV and current post-harvest depuration is inefficient in its removal. While NoV can be inactivated by cooking (e.g. mussels), consumption of contaminated raw shellfish (e.g. oysters) represents a risk to human health. Consumption of contaminated food accounts for 3-11% of NoV cases in the UK (~74,000 cases/year), of which 16% are attributable to oyster consumption (11,800 cases/year). However, environmental and human factors influencing NoV infectivity remain poorly understood. Lack of standard methods for accurate quantification of infective and non-infective (damaged) NoV particles represent a major barrier, hampering identification of an appropriate lower NoV contamination limit for shellfish. Future management strategies may include shellfish quality assessment (at point of harvest or at point of supply) or harvesting controls. However, poor understanding of NoV inactivation in shellfish and the environment currently limits accurate apportionment and risk assessment for NoV and hence the identification of appropriate shellfish or environmental quality standards.