Removal of toxic lead from aqueous solution using a low-cost adsorbent.

Valorization of waste materials and byproducts as adsorbents is a sustainable approach for water treatment systems. Pottery Granules (PG) without any chemical and thermal modification were used as a low-cost, abundant, and environmentally benign adsorbent against Pb(II), the toxic metal in drinking water. The porous structure and complex mineral composition of PG made it an efficient adsorbent material for Pb(II). The effect of key physicochemical factors was investigated to determine the significance of contact time, PG dose, pH, solution temperature, and coexisting ions, on the process. Pb(II) removal increased by PG dose in the range of 5-15 g/L, and agitation time from 5 to 60 min. Increasing Pb(II) concentration led to a drop in Pb(II) removal, however, adsorption capacity increased significantly as concentration elevated. Pb(II) removal also increased significantly from ~ 45% to ~ 97% by pH from 2 to 12. A ~ 20% improvement in Pb(II) adsorption after rising the solution temperature by 30˚C, indicated the endothermic nature of the process. The sorption was described to be a favorable process in which Pb(II) was adsorbed in a multilayer onto the heterogeneous PG surface. The qmax of 9.47 mg/g obtained by the Langmuir model was superior among many reported low-cost adsorbents. The Pb(II) adsorption was described well by the Pseudo- first-order kinetic model. Na+, Mg2+, Ca2+, Cd2+, and Zn2+ showed a negligible effect on Pb(II) adsorption. However, the presence of Mn2+ and Fe2+ significantly hindered the process efficacy. In conclusion, the use of waste material such as PG against Pb(II) is a viable option from the economic and effectiveness points of view.

Chemical and microbial quality of bottled drinking water in Gonabad city, Iran: Effect of time and storage conditions on microbial quality of bottled waters.

Reports from bottled water (BW) industries show a rapidly increasing rate of global bottled water consumption. The present paper contains data on chemical and microbial quality of bottled waters marketed in Gonabad city, Iran. The data on the effect of time and storing conditions on microbial quality of bottled water also is reported. The physical and chemical parameters of all 9 studied BW brands meet well with those mentioned on the labels. All BW sampled also were free of pathogenic indicators (total coliforms, fecal coliforms, fecal streptococci and clostridium perfringens). BWs kept in refrigerator have minimal heterotrophic and pathogenic bacterial count. The highest bacterial count was observed when BWs were exposed to indirect sunlight at room temperature. Presence of heterotrophic and especially pathogenic bacteria reduced significantly when the samples were placed to direct sunlight. In all samples, apart from where they were kept, the heterotrophic and pathogenic bacterial counts showed an increasing trend after bottling.

Data on efficient removal of acid orange 7 by zeolitic imidazolate framework-8.

A water stable and hybrid nonporous adsorbent, cubic zeolitic imidazolate framework-8 (ZIF-8), was synthesized for Acid orange 7 (AO7) removal from aqueous solutions in batch mode. Central composite design was utilized to explore the individual and interaction effects of pH, AO7 concentration, ZIF-8 dosage and contact time on dye adsorption. A second order polynomial equation (R2 = 0.9852, LOF = 0.1419) developed for prediction of the AO7 removal. Sorption model revealed that the adsorbent dosage and the dye concentration are major factors that controlled the AO7 removal efficiency. AO7 removal increased from 55 to 80% by increasing ZIF-8 dosage from 0.2 to 1 g/L. The dye removal, on the other hand, decreased from 84 to 70% with increasing AO7 concentration from 10 to 100 mg/L and increased from 60% to 80% by decreasing pH from 12 to 4. The dye removal followed the pseudo second order kinetic and the Langmuir isotherm model. The maximum monolayer adsorption capacity of 80.47 mg dye/g of ZIF-8 was obtained according to the Langmuir model.

Cadmium in Groundwater Consumed in the Rural Areas of Gonabad and Bajestan, Iran: Occurrence and Health Risk Assessment.

Evidences show that high levels of cadmium intake may be contributing to a wide range of deleterious health effects. This study was performed to estimate the concentration of cadmium and the health risk to human by cadmium through the ingestion of groundwater in 39 rural areas of Gonabad and Bajestan, eastern Iran. The mean cadmium concentrations in groundwater in the studied rural areas of Gonabad and Bajestan ranged from 0.087 to 14.32 µg/L and from 0.417 to 18.36 µg/L, respectively. Health risk quotient for cadmium contamination for 16 and 38% of children and infants in rural areas of Gonabad and Bajestan, respectively, was more than 1 which causes non-carcinogenic risk to the local population. The carcinogenic risk of cadmium in drinking water for adults, children, and infants in 16, 33, and 33% of studied rural areas of Gonabad and Bajestan, respectively, was higher than the safe limit of 1.0 × 10-4. For rural areas of Bajestan, the cancer risk in 42, 52, and 52% of adults, children, and infants was above the safe limit. It was strongly suggested that the accessible procedures of treatment should be taken for a portion of contaminated rural areas before the distribution of the groundwater for the local population.

Phenol removal from aqueous solution using Citrullus colocynthis waste ash.

Phenol is a hazardous organic chemical that introduced into the environment by industrial and pharmaceutical discharges. As a versatile option for phenol removal, adsorption would be viable if it accompanying with low cost adsorbents. This article described a natural, very cheap and local available adsorbent for phenol removal. Phenol showed a high affinity to Citrullus colocynthis waste ash which mainly composed of SiO2 (41.6%), Al2O3 (17.3%) and MgO (15.9%). Up to 70% of phenol adsorbed in the first 30 min of agitation. The phenol removal was increased by increasing adsorbent dose (0.5-10 g/L) and decreasing pH (2-12) and pollutant concentration (10-100 mg/L). The positive value of ∆H° in thermodynamic data (0.06) revealed that the process is endothermic. The high and positive value of ∆S° (13.01) and negative values of ∆G° (- 5.36 to - 7.28), showed a high affinity of phenol to the adsorbent and the spontaneous nature of the adsorption. Isotherm modelling revealed that the phenol molecules adsorbed in multilayer with the maximum adsorption capacity of 173.2 mg/g. The rate limiting step in the sorption process was chemisorption, based on the kinetic data.

Data on cadmium removal from synthetic aqueous solution using garbage ash.

This data article investigates cadmium removal efficiency using garbage ash as a cheap and effective adsorbent. Influence of different parameters, such as initial cadmium (II) concentration (mg/L), contact time (min), adsorbent dose (gr/L), pH and temperature (°C) were investigated. The characterization data of the garbage ash was determined using SEM analysis. The experimental data indicated that the adsorption of cadmium on garbage ash follows pseudo second order model and Langmuir isotherm model with R2 = 0.99. Also, the maximum adsorption capacity of adsorbent was 100.25 mg/g. Thermodynamic data showed that cadmium adsorption on garbage ash was a spontaneous and endothermic process. Based on acquired data, garbage ash could be proposed as an efficient and low-cost adsorbent for the removal of cadmium from aqueous solution.