A waste biomass based hydrogel soybean residue-poly(acrylic acid) (SR-pAA) was prepared through a fast one-step reaction by UV radiation technology. SR-pAA was used to remove cd(ii) and pb(ii) ions from aqueous solutions. Effect of pH value, temperature, initial concentration, contact time, competitive ions in the solutions on metal ions adsorption and desorption/regeneration capacity of SR-PAA was discussed in detailed. It was found that the adsorption equilibrium was achieved within 20 min, and maximum adsorption for Cd(II) and Pb(II) ions were 1.43 and 2.04 mmol g −1 , respectively. Besides, adsorption thermodynamic analysis indicates that the process of cd(ii) and pb(ii) ions adsorption was spontaneous, feasible and exothermic in nature. And experimental data fitted the pseudo-second-order and freundlich isotherm model well. Moreover, XpS spectra analysis proves that the metal ions were adsorbed on SR-pAA due to the interaction of carboxyl, hydroxyl and amine with these ions as ionic bond, coordination bond and electrostatic interaction. Increasing industrialization has brought great challenges to the environment. Like China, many countries face more and more enormous environmental problems, especially water pollution caused by heavy metal ions 1-3. Among various heavy metals, Cd(II) and Pb(II) have strong toxicity, which can damage to animals and human bodies seriously though the food chain. The report from United States Environmental Protection Agency showed that cadmium can cause respiratory cancers, for example, lung carcinoma 4 , and lead can cause cognitive dysfunction in children, hypertension, immune system and reproductive system diseases 5. Consequently, it is particularly necessary to remove the heavy metal ions from the wastewater before discharge it into the environment. Adsorption is a common method to remove various heavy metal ions from the wastewater. Many kinds of adsorbents, including activated carbon 6 , inorganic minerals 7 , biomass adsorbents 8-10 , and polymer 11-14 , are used to remove the metal ions from the wastewater. Metal ions adsorption capability of an adsorbent is mainly controlled by the surface active sites (functional groups such as carboxyl, hydroxyl, amino and hydrosulphonyl) of the adsorbent 15. The metal ions that contact with the adsorbent surfaces may be attached to the surfaces of the adsorbent according to physical or chemical interaction. Then those metal ions can be adsorbed on the adsorbent by ion exchange, coordination interaction, electrostatic interaction and physical adsorption, which are considered to be the main mechanism of most adsorbents to remove metal ions. In particular, it has been reported that the group of carboxyl, hydroxyl and amino are extremely advantageous to the metal ions removal from various aqueous solutions 6,9,16-19. Hence, many researchers are interested in the functional groups modified adsorbents to enhance the capability of metal ions removal. However, an efficient, low-cost, easily obtained and environmental friendly adsorbent is ve...

Recently, surface-enhanced Raman Spectroscopy (SERS) has been widely applied for rapid detection of trace targets in various fields. However, two key issues are still being explored: (1) how to form effective “SERS hotspots” for the trace qualitation with high sensitivity; (2) how to quantitatively identify trace target in complicated matrix in a highly selective and fast manner. Here, aiming at these two key points, we developed an effective and simple protocol for the rapid detection of three tropane alkaloids (TAs), typical toxicants in public security. Taking the advantage of the coadsorption with the specific adsorbed I− during the formation of hotspots by the highly concentrated halide salts, the detection sensitivity of TAs was improved up to 4 orders over the case of Cl−. Under the optimized condition, the lowest detectable concentration of these three TAs was down to the 1 μg/L level. Through the use of drink and food samples, the strong nonspecific competitive adsorption from the complicated matrix was significantly weakened by the simple dilution. The recovery was increased almost 2 orders over that of direct detection, irrespectively of the distinctly changed interferences in different samples. The proposed strategy, improving qualitative sensitivity by forming effective hotspots and quantitative analysis by dilution, not only provides a rapid detection for trace TAs in various foods in case of emergency first response but also could be easily extended to other SERS-based analysis.

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